A radio-frequency circuit (20) includes a hybrid integrated circuit (24) having a passive circuit element (38) and a d-c biasing circuit element (54) embedded within a first substrate (32) of a low cost and rugged first semiconducting material, and first and second active circuit elements (36, 40) embedded within second and third substrates (44, 46), respectively, of a second semiconductor material having the characterisitics of greater frangibility but higher gain than the first semiconductor material. The first and second activ circuit elements (36, 40) are substantially first and second single components (36, 40), and are each electrically coupled to the passive circuit element (38). The d-c biasing circuit element (54) is electrically coupled to the first and second active circuit elements (36, 40). The second and third substrates (44, 46) are physically coupled to the first substrate (32), which is thicker than either the second or third substrate (44, 46).

High-density microwave or millimeter-wave circuitry is often photolithographically fabricated upon a semiconductor substrate. Gallium arsenide (GaAs) is ordinarily the semiconductor of choice, offering significant increases in gain over other semiconductors (e.g. silicon) at the desired frequencies.
Several problems arise in the use of gallium arsenide substrates. As a material, gallium arsenide has a high frangibility. This high frangibility leads to an increase in wafer breakage during the circuit fabrication process, hence reducing the effective circuits-per-wafer yield. This is especially pronounced for large circuits having low initial circuit-per-wafer densities.
High frangibility also means that large gallium arsenide circuits are more likely to suffer damage from shock and vibration than are similar circuits in other materials. This can become a limiting factor in the design of devices which must be able to tolerate high G-forces (such as handheld telephones, which may be dropped) and extremes of pressure and vibration (such as a satellite during launch).
Gallium arsenide also suffers from poor thermal conductivity. Poor thermal conductivity requires that gallium arsenide substrates be thin to allow for adequate heat sinking and power dissipation. Making a given gallium arsenide substrate thin, however, exacerbates the specific frangibility of that circuit, and increases the possibility of device failure.
Among semiconductors, gallium arsenide is inherently expensive. Also, the fabrication techniques required of gallium arsenide are themselves more expensive than those of other semiconductors. A given gallium arsenide circuit may be sufficiently expensive, compared to a similar circuit in silicon, so as to prohibit fabrication in production quantities. Thus, those applications where the use of gallium arsenide would be most desirable may also be the very applications where the cost of gallium arsenide would severely limit its use. For example, a phased antenna array, having a thousand active elements coupled to a thousand gallium arsenide circuits, may be prohibitively expensive for commercial applications.
What is needed is a way to create circuits with the high gain of gallium arsenide at microwave and millimeter-wave frequencies, while minimizing the effects of the high frangibility and low thermal conductivity of gallium arsenide as well as the material and fabrication costs thereof.


The present invention provides a process of decontaminating, by composting under specific conditions, soil and/or sediments containing certain toxic cyclical organic compound contaminants by converting these contaminants into harmless materials. The compounds include chlordane, dieldrin, toxaphene, aldrin, endrin, and heptachlorepoxide. The process includes the step of affecting a solid compost mixture during composting with a redox potential below negative 200 mV (millivolts). Further, the process includes several steps which are repeated until an amount of contaminant is degraded to less than 140 ppm (part per million) per ton of soil.

This invention relates to a controlled composting process for decontaminating soil and/or sediments containing one or more of certain toxic cyclical organic compound contaminants, namely chlordane, dieldrin, toxaphene, aldrin, endrin, heptachlor, methoxychlor, heptachlorepoxide, and alpha, beta, gamma and delta benzene hexachlorides, hereinafter referred to collectively and singly as "chlorinated contaminants".
Numerous land sites exist that are contaminated with the chlorinated contaminants. Most of these contaminants are toxic pesticides and many are believed to be carcinogens. Various methods have been used to decrease the contamination of the soil including incineration, low temperature thermal desorption and chemical treatments. All of these methods are extremely expensive and may not be suitable for many contaminated sites.

Compost decontamination of soil contaminated with chlorinated toxicants


A submount for a semiconductor laser. The submount has a layer of silicon carbide (SiC) and a layer of aluminum nitride (AlN) deposited on the layer of SiC. The submount is bonded to the InP-based laser by a hard solder applied to the AlN layer. Preferably, the thickness of the AlN layer is ten to twenty microns, the thickness of the SiC layer is two hundred fifty microns, and the solder is a gold-tin (AuSn) eutectic. The semiconductor laser may be a quantum cascade laser (QCL). Similar combinations of submount materials can be found for other semiconductor laser material systems and types.

High power semiconductor lasers, because of their small physical dimensions and high electrical power input, require special thermal management considerations. In addition to effectively extracting the waste heat (net of electrical power input and optical power output) from the active semiconductor laser region, considerable attention needs to be paid to ex-chip thermal management. The waste heat needs to be removed from the semiconductor laser mounting surface efficiently so that the active region of the laser remains at the proper operating temperature. Typical semiconductor laser package assembly involves bonding of the laser to a submount (substrate material) that, in turn, is mounted on a heat spreader or a heat sink.
Three critical parameters need to be considered when choosing the substrate (submount) on to which the semiconductor laser chip is mounted. The first is the thermal conductivity of the submount, which needs to be as high as possible to remove the heat efficiently from the laser. The second is the coefficient of thermal expansion (CTE) of the submount with respect to the coefficient of thermal expansion of the semiconductor laser material. The CTE of the submount must be close to that of the laser to minimize mechanical stress in the laser chip during large temperature cycles, both during the operation of the laser but also during the mounting process which, for reliability purposes, typically uses AuSn eutectic or other hard solder. Third, it is inconvenient to mount the chips directly onto heat spreaders and heat sinks because the heat spreaders are usually bulky. Furthermore, it is much easier to do proper metallization for laser interconnections on a compact submount wafer that is subsequently diced into individual submounts.
One of the most widely employed and technologically important submount materials for InP-based semiconductor lasers is aluminum nitride (AlN). Its CTE, being 4.5×10−6 K−1, is perfectly matched to that of indium phosphide (InP) at room temperature, essentially eliminating thermally induced mechanical stresses on the laser structure, both those frozen-in after die mounting and those arising from thermal cycling during device operation. In addition, high-grade AlN exhibits high thermal conductivity of ˜200 W/mK at room temperature. This value is three times higher than thermal conductivity of InP (70 W/mK), which naturally enhances heat transfer from the laser active region into the heatsink. Finally, AlN is an electrical insulator, and hence it permits easy formation of electrical interconnects on the submount for incorporating various passive monitoring elements into the integrated chip on carrier assembly. Due to the advantages listed above, AlN is one of the most widely used materials for semiconductor laser submounts. Similar combinations of submount materials and semiconductor laser materials can be found for other situations.
However, even though AlN has a relatively high thermal conductivity, higher laser performance can be achieved employing submount materials with even higher thermal conductivity. This is especially true for high-power continuous-wave quantum cascade lasers (QCLs) that generate up 30 W of waste heat, from a surface area typically 200 μm wide and 5-7 mm long, and whose performance deteriorates rapidly as the active region temperature rises.
Diamond has the highest known thermal conductivity (>1800 W/mK) of all natural materials, exceeding that for AlN by more than a factor of nine. Therefore, employment of diamond submounts is expected to significantly reduce laser active region temperature under the same laser driving conditions. However, the CTE of diamond at room temperature is ˜1×10−6 K−1. Thus, the CTE mismatch between InP and diamond is very large. So, to avoid the undesirable mechanical stress, it is necessary to use soft solders, such as indium, for laser bonding. Soft solders suffer from electromigration from the bonding area to the laser facets, which eventually leads to electrical shorts, facet damage, and eventual laser destruction. This significantly reduces laser reliability. Therefore, diamond is rarely used as a submount material for commercial semiconductor laser applications.
We identified another material that is significantly superior to AlN for high heat waste applications, namely silicon carbide (SiC). SiC has a thermal conductivity of up to 600 W/mK, three times that for AlN. As with AlN it can be made semi-insulating, which facilitates all the electrical interconnects. In addition, its CTE mismatch with InP can be less than 1.0×10−6 by proper choice of orientation and structure of SiC. It is worth noting that this mismatch is almost a factor of five smaller than that of InP on diamond. But even this relatively small CTE mismatch can still lead to reduced laser reliability, especially when the final assembly undergoes large thermal cycles during packaging and subsequent laser operation.


The present application discloses method for generating a panorama image based on a rendering engine associated with a display apparatus. The method includes determining a display model configured to be a polygon prism for a rendering engine corresponding to a panorama view of a scene. Additionally, the method includes using multiple sampling cameras associated with the rendering engine to capture multiple sample sub-images of the panorama view in respective directions towards multiple sub-planes of the polygon prism. The method further includes attaching the multiple sample sub-images to respective multiple sub-planes to form a constructed display model. Furthermore, the method includes rendering the constructed display model by the rendering engine to reconstruct a panorama image and displaying the panorama image on the display apparatus.

In some applications, mobile virtual reality (VR) apparatus needs to display a panorama image instead of rendering real scene in real-time to smoothly play the VR video. A conventional panorama image includes a single 360° image generated from a texture model in a sphere shape. Several issues existed with this sphere model include 1) display image distortion caused by the patch aggregation of the single panorama image in vertical direction from a top point to a bottom point of the sphere model; 2) limitation of maximum image resolution of an image in a certain field-of-view angle due to lack of decoding ability in image's pixel resolution of the single panorama image under the same field-of-view angle.

Method for generating and displaying panorama images based on rendering engine and a display apparatus

BEIJING BOE OPTOELECTRONICS TECHNOLOGY CO., LTD.


A vehicle sunshade including a foldable screen dimensioned for mounted coverage of a vehicle roof top opening with a leading edge dimensioned for removable attachment to a front periphery of the opening and a rear portion adapted for removable mounted engagement with a corresponding rear portion of the opening and having a magnetic coupling portion extending in a width direction from opposing side edges in substantially parallel alignment to the leading edge such that magnetic coupling of the magnetic coupling strip with the leading edge detachably affixes the sunshade to cover the opening and an interposed live hinge having a front panel flexibly pivotable about a hinge line thereby providing a taut and continuous planar surface when the magnetic coupling portion is coupled and enabling the front panel to fold back over an abutted surface of the rear panel when the magnetic coupling strip is decoupled.

Open roof sunshades are very popular with owners of sport utility and similar vehicles. Among other things, they offer the owner the option of being able to shade or screen the sun while maintaining an open roof top for ventilation and fresh air experience. To readily accommodate changing weather conditions and glare emitted and reflected from the sun as well as roadside and other vehicles lamps, it is important that the design of the top be easy and convenient to operate in order or facilitate expeditious positioning of the sunshade between use and folded positions. It is also desirable that minimal space is used when the sunshade is not in use and that the hardtop may be readily accessible, particularly during sudden onsets of rain and inclement weather.
Conventional soft panel top assemblies for vehicles typically include a frame, typically foldable, with a soft convertible top that may be tautly assembled when the frame is pulled or pivoted to an upright or extended position. Prior art soft tops may also include a sunshade cover typically extended along opposing rails to an unwound position over a roof opening and wound about a rotatable shaft in a winding tube in a folded position such as described U.S. Pat. Nos. 9,067,480 and 10,099,543. Such existing sunscreen assemblies typically include multiple layers of flexible fabric imparting a bulky construction. Moreover, frames or winding mechanisms of conventional vehicle sunshades for an open vehicle roof often require disassembly and storage to provide necessary clearance for placement of a hard top on the opening.
As a result, such conventional sunshades and soft panel vehicle roof top assemblies are bulky, require multiple steps to assemble, extend and store and lack a streamlined, facile application enabling ready closure when extended to a use position and minimal space leaving clearance for securing a hard top without requiring removal or disassembly.
Accordingly, there persist an ongoing need for a streamlined, compact and facile sunshade for roof top openings that does not detract from the experience of operating the vehicle roof top cover components and the feel of outdoor air.

Vehicle sunshade assembly with magnetic coupler


An apparatus is provided. The apparatus includes an amplifier, differential amplifiers, and FETs. The amplifier has an intermediate node and an output node, and the amplifier is adapted to receive an audio signal. Each differential amplifier amplifies the difference between an output voltage from the output node with a reference voltages. The FETs are coupled in series with one another between a first and a second voltage, and each FET receives an output from at least one of the differential amplifiers. Additionally, the intermediate node is coupled to a node between at least two FETs.

Audio amplifiers are a class of signal amplifiers used in a wide variety of electronic equipment, including stereo audio systems, televisions, personal media players, and cellular phones. Some of these amplifiers drive speakers, such as those in a stereo audio system or television, while others typically drive headphones, such as those used with personal media players and cellular phones.
In many cases it is desirable to limit the peak or average audio output level delivered to headphones, to preclude hearing loss from excessive sound pressure levels. Many devices driving headphones, such as compact disc players, MP3 players, and portable DVD players incorporate circuitry to limit audio output levels delivered to headphones.
One known approach is the use of an automatic gain control (AGC), which compares the peak or average audio level to a threshold, and decreases the amplifier gain so as to reduce output level for some time period after this threshold is exceeded. Such circuits typically have time constants with relatively fast attack and much slower decay to reduce audible effects of the AGC operation. To minimize the undesired modulation of the audio level by the AGC, sometimes referred to as "pumping", the time constant for decay is often seconds long. This long time constant often leads to an undesirable characteristic wherein a brief sound above the threshold level, for example a loud cymbal, causes a rapid reduction in output level, not only of the brief sound which exceeded threshold but of all sound for the next several seconds. Following the over-threshold audio, if the audio levels remain below threshold sound level, the amplitude of the audio will gradually increase, at a rate set by the decay time constant, until gain is again at its nominal level. This gain change during music leads to undesired distortion of the dynamic range of the audio, and also may cause soft music following a loud musical peak to be so low in level as to be difficult to hear.
Another known approach to limiting the output level of an audio amplifier is the use of clipping of the audio signal on a cycle by cycle basis. A clipper simply replaces any portion of an audio waveform which otherwise would be above a threshold level with a constant voltage at the threshold level, until the waveform voltage again falls below threshold. There is typically no intentional gain change caused by such clipping, and the time constant for clipping is typically much faster than the period of a single cycle of audio, even at its highest frequencies.
Clipping therefore avoids the dynamic range modulation artifacts or "pumping" associated with an AGC, and causes little or no change in audio levels which stay below the clipping level. However, clipping of those portions of the waveform which otherwise would have exceeded the threshold level causes significant increases in harmonic distortion, due to the introduction of abrupt discontinuities in the audio waveform at the start and end of clipping for each cycle.
Some examples of prior art devices can be seen in U.S. Pat. Nos. 3,737,678; 3,818,244; 5,737,432; and 7,155,020.
An apparatus and method for limiting the output level of an audio amplifier, which causes less dynamic range modulation than an AGC and less harmonic distortion than known clipping circuits, is therefore desirable, and is an object of the present invention.

Feedback controlled power limiting for signal amplifiers


In order that a moving locus of a leading end of a tool 55 provided to a tool mounting device 54 is aligned with a direction orthogonal to a center line W of a wire rod passage (not shown) of a final wire rod guide 13, a tool operating apparatus 22 has a position adjusting table 23 movable forward and backward and movable to optional positions within a virtual vertical plane parallel to a front wall 5 of an upper portion 2B of a fixed machine casing 2, a rotating body 46 provided to the position adjusting table 23 rotatably around a rotation center line C parallel to the center line W of the wire rod passage of the final wire rod guide 13, and a tool mounting device 54 provided in the rotating body 46 movably in parallel in a direction orthogonal to the rotation center line C.

1. Field of the Invention
The present invention relates to a spring manufacturing machine.
2. Description of the Conventional Art
In conventional, as this kind of spring manufacturing machine, the following structure has been known.
There has been known a spring manufacturing machine which delivers a wire rod to a wire rod processing space from a final wire rod guide, and applies a predetermined process to the wire rod which was delivered or is being delivered to the wire rod processing space by a tool which will protrude or is in a protruding state to the wire rod processing space so as to manufacture a spring, wherein a tool operating apparatus is provided in such a manner as to oppose to the final wire rod guide beyond the wire rod processing space, and the tool operating apparatus has a position adjusting table provided so as to freely move forward and backward with respect to the final wire rod guide, a rotating body provided so as to freely rotate around a rotation center line arranged in alignment with a center line of a wire rod passage of the final wire rod guide in the position adjusting table, and a tool mounting device provided so as to freely oscillate along a virtual plane including the rotation center line, in the rotating body (refer to Japanese Patent Publication No. 6-2296).
The conventional spring manufacturing machine has the following defects.
Since the tool mounting device is provided in the rotating body so as to freely oscillate, a moving locus of a leading end (a leading end opposing to the final wire rod guide) of the tool provided in the tool mounting device forms a circular arc, by moving the tool mounting device from a retracted position to a working position, so that it is hard to execute a position control for stopping the leading end of the tool at a set position with respect to an outlet of the final wire rod guide. Further, in the case that a play exists in a power transmission link mechanism of the tool mounting device, the leading end position of the tool is displaced from the set position. However, since the position displacement appears as a displacement in a direction orthogonal to the center line of the wire rod passage of the final wire rod guide, and a displacement in a direction parallel to the center line of the wire rod passage of the final wire rod guide, there is a defect that the position displacement greatly lowers accuracy of form of the spring.


The function addressed is that of adaptive equalization to mitigate the effects of multiple path radio propagation in the context of point-to-multipoint, time division duplexed microwave radio systems. Without this equalization, fading and intersymbol interference degrades the accuracy of the recovered bit stream. This degradation of the received signal is caused by the vector sum of multiple copies of the transmitted signal arriving with various time offsets and amplitudes. The method employed uses a single training symbol per frame common for all time division multiplexed derived channels rather than one for each channel and for both up and down directions. Compensation is applied at each station transmitter rather than separately equalizing each received signal at the common receiver.

1. Field of the Invention
The function addressed is that of adaptive equalization to mitigate the effects of multiple path radio propagation within the below stated context. Without this equalization, fading and intersymbol interference degrades the accuracy of the recovered bit stream. This degradation of the received signal is caused by the vector sum of multiple copies of the transmitted signal arriving with various time offsets and amplitudes,
Prior art methods are only economically applicable to point-to-point links. Such prior art methods applied to point-to-multipoint, two-way links are not only uneconomic but consume excessive channel time.
The context of this invention is radio-linked, high-data-transfer-rate communication at microwave frequencies. More specifically, the context is in the use of the radio path for communication between one fixed access point common to and serving multiple variously located user stations. The context is limited to the further subset in which time division duplex is used alternately to transmit up and down link information on a single radio channel. In this context, the radio path is identical in either direction when the same antenna is used for both transmitting and receiving; and the communication of each station is time division multiplexed on the common radio channel.
2. Description of the Prior Art
Prior art time division multiplexing requires that each station transmit in short bursts preceded by a preamble from which the receiver must condition itself for the body of the message. Time division may be with regular slots as is the case for virtually all telecom applications, or at irregular intervals as practiced in computer local area networks transferring packets. If a system must perform both of these functions, it is convenient and advantageous to have regularly periodic frames tied to the public network timing function. A reasonable choice of frame period is equivalent to 48 octets (8-bits) every 6 milliseconds to provide a virtual circuit of 64 Kbps. For voice circuits requiring only 32 Kbps, an alternative is to use only every other frame. The number 48 is the octet payload size of one cell in ATM (asynchronous transfer mode) communication.
Equalization Function
Prior art equalization occurs in the developing European Local Area Network Standard known as HIPERLAN (High Performance Local Area Network) prepared by the ETSI RES 10 Committee. In this system, each transmitted burst is at rate of 25 Mbps and begins with a "training symbol" of 480 bits that enables the destination receivers to infer the compensation necessary from the difference between the actual received signal and its known original pattern. Considerable system channel time is required for this function because it is required on every transmission regardless of its size.
From limitations on access and transfer delay across the system, it is undesirable to have long bursts. For telecom, the quantizing delay is the period of time required for the necessary number of octets to be accumulated in a buffer. For good transmission reasons, it is undesirable for this delay to exceed 12 milliseconds. With voice bandwidth compression, this number is commonly exceeded in many telephone systems, and which then require echo cancellation circuits.
One ATM cell is 53 octets or 424 bits. Several additional octets must be added for radio system overhead and acquisition preamble. It may be seen that the length of the training symbol is about the same as length of time required to transmit the useful information and logic overhead.
The prior art methods accumulate multiple cells to form longer bursts diluting down the equalization overhead. The penalty for the use of longer bursts is proportionally longer quantizing, transfer and access delay. The penalty is yet greater in prior art systems that are fundamentally peer-to-peer asynchronous (no regular frame structure), because then the training symbol must be used as well for every down link transmission in addition to every up link transmission.
Theoretical Basis
The invention uses two steps which apart from each other are prior art. The first step is measuring the impulse response of the medium. The second step is defining the transmitted pulse shape which compensates the time dispersion of the medium to provide the original pulse shape with low distortion at the destination receiver.
Impulse Response Defined Transmission Medium
A valuable reference on this subject has been provided in "Filtering in the Time and Frequency Domain" by H. J. Blinchikov and A. I. Zverev. In this reference, the following paragraph appears:
"We now have reached the amazing conclusion that a linear system with constant parameters is uniquely characterized by the single function h(t), which is the system response to an impulse function applied at t=0. It is this function that is termed the system'impulse response to an arbitrary input by the way of the convolution integral." PA1 "Convolution and Deconvolution Convolving the impulse response of a digital filter with an input signal generates the corresponding filtered output. This document shows two ways of carrying out convolutions in MathCAD: . . . . The document also illustrates recovery of the original signal by deconvolution; you can carry out deconvolution efficiently in MathCAD by dividing the FFT of the output sequence by the FFT of the filter impulse response." "Electrical Engineering Application Pack--MathCAD," Copyright 1989 by MathSoft, Inc., One Kendall Square, Cambridge, Mass. 02139 (Page 93 of the Manual)
Barker Codes to Sound Medium and Observe Impulse Response
If the transmitted signal is a Barker code, the received signal is the impulse response of the medium with the degree of resolution and freedom from ambiguity limited by the code length. A 13-bit Barker will resolve paths arriving with one bit of time difference, and will lose accuracy from the ambiguity of response delayed longer than the 13-bit symbol. Longer codes will deal with larger amounts of time dispersion as a multiple of symbol length. The Barker is in effect a bandwidth limited pulse driver. The invention uses this information in the form of polar samples over the duration of the symbol. Averaging of repeated measurements decreases the uncertainty of these samples due to noise added in transmission. This technique is prior art.
Finite Impulse Response Pulse Shape Formation
There is art in generating the pulse shape representing the individual bits to obtain a defined and minimized frequency spectrum. To apply transform mathematics, this pulse shape must be mathematically and not empirically defined. A good pulse shape has been found to be the well known duo-binary pulse shape compressed to 2/3rds of its normal period. Each pulse, optimized for the distortionless medium, is given by equation 2! below. EQU T.sup.2 sin(.pi.t/T)/.pi.t(T-t) duobinary 1! EQU (2T/3).sup.2 sin(3.pi.t/2T)/.pi.t((2T/3)-t) compressed duobinary2!
The width of the main lobe of this pulse is spread over two bit intervals (as given by equation 2! above, rather than the three intervals of well-known duobinary pulses, as given by equation 1!). A short string of such pulses with polarity corresponding to a few different binary sequences results in a composite pattern as shown in FIG. 8 of Rypinski U.S. Pat. No. 5,388,126.
Consecutive pulses of the same sign add to a near constant dc level provided the detail of the low amplitude parts of the pulse extending a few bit intervals before and after the main lobe are taken into account. The capacity to define and generate a pulse shape extending over several bit intervals is what makes possible the use of this type of pulse shape which extends over several bit intervals and many of which must be overlaid in accordance with the data pattern. Modulations employing pulse shapes defined over plural bit intervals are referenced as "partial response" types.
The modification of this pulse shape to offset multipath time dispersion also must be made over a period of several bit intervals.
The use of Finite Impulse Response (FIR) filters to generate this and other pulse shapes is prior art. A convenient hardware method is based on shift register stepping at a sample rate which id a small integer multiple of the bit rate, where the pulse shape generated depends on the value of preceding and following bits as well as the current bits.
The impulse response is a measure of the medium. A new function must be generated which undoes the time and amplitude dispersion. This is similar to taking the pulse shown as an input and concentrating it back to the very narrow pulse that was used to generate the received shape.
Convolution and Deconvolution
These mathematical arts are described in the literature, where the functions are manipulations using the Fast Fourier Transform. The calculation of the needed wave shapes can be done with available computer applications, for example:
Station Transmit Pulse Shape
The desired transmit pulse shape is one which, after passing through the distortion introduced by the line as defined by the impulse response, produces the same pulse shape as was defined for the distortionless line.
The desired transmit pulse shape is calculated as one that a time convolution integral performed on the transmit pulse and the transmission medium impulse response produces the pulse shape defined for the distortion free medium.
This definition starts from the answer and works backward. The method of calculation uses the previously referenced deconvolution procedure.
Known Impulse Response Characteristics
In the last few years, a great deal of data has been collected on the propagation characteristics of microwave radio paths in buildings and on streets including measurements of quantities of impulse responses and their statistical evaluation. In particular NTIA-ITS (National Telecommunications and Information Administration, Institute for Telecommunication Sciences) has made high resolution polar measurements of impulse response at 1.5 Ghz in office and other environments.
The data presented includes samples of best and worst case responses, and statistical evaluation of large collections of samples vs. distance in several different environments. This kind of information is very important to the proportioning of the data rate and equalization symbol length.
This data is used to characterize the problem and its numeric proportions. The data is not used in any way in the parameters of the application of the invention.

Frame format and method for adaptive equalization within an integrated services wireless local area network


A hand glove for the participant of an active sport in which at least one of the participants fingers maybe subjected to hyper-extension from contact received from participating in that sport. The glove has respectively oppositely disposed palm and dorsal faces, a plurality of individual finger elements and an elongate strip of material having at least elastically stretchable portions spaced apart from one another longitudinally along the strip and on the palm face side of the glove for each one of selected finger elements of the glove. Each strip is anchored at one end thereof proximate the tip of the glove finger element associated therewith and at the other end proximate the palm portion of the glove. Each strip being elastically stretchable is tensioned causing the finger element associated therewith to curl in a direction of the fingers for gripping an article.

A risk attendant with some sports, for example, a soccer goal keeper is the hyper-extension of finger joints or thumb or wrist injury. It is known to use hinged strips in the finger elements of the glove to reduce the likelihood of finger joint hyper-extension. The hinged strips allow flexing in a gripping direction of the hand but block bending in an opposite direction.
The proposed directional flex strips are complicated and thus expensive items to produce. Also they are bulky occupying considerable finger space. It is also known to provide gloves with specialized padding or cushioning. For further information on various proposals reference maybe had to the following references: United States Published Application No US 2005/0153153 A1 Published Jul. 14, 2005; U.S. Pat. No. 6,557,177 granted May 6, 2003; U.S. Pat. No. 5,720,047 granted Feb. 24, 1998 and PCT application WO 01/00052.
As previously mentioned a further use of applicants glove could be that of an exercise device. As an example of one such known unit reference maybe had to U.S. Pat. No. 5,453,064 granted Sep. 26, 1995 and entitled "Exercise Glove Incorporating Rods Which Offer Resistance to Movement of Fingers, Hands or Wrists". Disclosed are flexible elongate "inextensible" strips insertable into pockets in the finger elements of the glove with applicant pointing out that the strips maybe straight or curved.

This patent is subject to a terminal disclaimer.

Glove with support for hyper-extension resistance


An aluminum alloy for use in castings, comprising 0.0005-0.01 weight % of Fe, 0.0005-0.01 weight % of Si, 2.5-6.5 weight % of Cu, 0.10-0.50 weight % of Mg, 0.001-0.40 weight % of Mn, 0.10-0.50 weight % of Ti, 0.20-1.2 weight % of Ag, 0.002-0.01 weight % of B, no more than 0.01 weight % of any other individual component aside from Al, and the balance Al. The aluminum alloy is thereby designed to provide improved toughness without detracting from tensile strength, proof stress, and hardness.

1. Field of the Invention
This invention relates to an aluminum alloy for use in castings.
2. Description of the Prior Art
In recent years, aluminum forgings have been in widespread use in aircraft materials and industrial rotors. However, these forgings have problems such as difficulties in forging as well as high costs when complicatedly configured articles or large-sized components are required for formation.
As a way of overcoming such problems, castings using an Al--Cu--Mg--Ag series aluminum alloy have come into service.
Although exhibiting higher strength, the aforesaid aluminum alloy castings have a drawback of lower toughness (elongation) when compared with the forgings. As matters stand, such castings are restricted for use in members that require reliability.


A film comprising in admixture a thermoplastic resin component comprising a thermoplastic resin component and a glass having a refractive index within 0.04 of the thermoplastic resin component, wherein the film has a haze of less than about 20%, total transmittance of greater than about 70%, and a coefficient of thermal expansion of about 20 to about 80 um/m/° C. measured over a temperature range of 20 to 70° C. The films are of particular utility in optical applications such as light diffuser films.

The present invention relates to transparent films and compositions, and in particular to transparent films for optical applications.
Polycarbonate (PC) is an engineering thermoplastic resin with excellent toughness and clarity. Due to its excellent performance characteristics, polycarbonate is used in many applications requiring optical quality, including compact disks, ophthalmic lenses, and as diffuser films in backlit display devices. Polycarbonate films offer a number of advantages over poly(ethylene terephthalate) (PET), films including higher heat distortion temperature (HDT), higher scratch resistance, and better performance under stringent environmental conditions.
One of the major performance demands of a diffuser film is dimensional stability. Generally, when polycarbonate films are used in this application, portions of the film near the hot lamp may expand, while film further from the lamp either does not expand or does not expand to a similar extent, resulting in warping or wrinkling in these portions of the film. This can lead to an optical waving effect that is evident by sinusoidal oscillations in luminance intensity across the display panel after exposure. This problem may become progressively worse as the area of the film increases, and as the environmental conditions become more stringent. For larger displays like those in liquid crystalline display television (LCD TV) there is a demand for more and brighter fluorescent lamps, hence exposing the back lit module (BLM) and display to higher temperatures.
There accordingly remains a need in the art for films that that will remain flat over a wide temperature range, i.e., films that are dimensionally stable and therefore non-waving in use. It would be a further advantage of the film maintained a combination of advantageous physical characteristics such as low haze, high percent transmission (% T), low yellowing, and/or improved melt stability. Such compositions can be used in making films that will retain flatness over a wide range of end use conditions.

Transparent films, compositions, and method of manufacture thereof


Aspects of the present invention concern the identification of several methods to analyze the genes that are modulated in normal human bronchial epithelial (NHBE) cells after exposure to cigarette smoke condensates (CSC) or cigarette smoke (CS). Embodiments described herein include methods to identify a gene that is modulated in response to exposure to CSC or CS, methods to identify tobacco products that have a reduced potential to contribute to tobacco-related disease, methods to make tobacco products that have a reduced potential to contribute to a tobacco-related disease, methods to identify a subject's predilection to acquire a tobacco related disease, the use of particular genes as biomarkers for tobacco-related disease, and patterns of gene expression or genetic signatures that are unique to each particular tobacco product.

The leading preventable cause of death and disability in the United States is the chronic use of tobacco products, in particular, cigarettes. In addition to lung cancers, tobacco use plays important direct and indirect roles in the etiology of a wide range of other cancers, including those of the upper aerodigestive tract (e.g., oral cavity, pharynx, larynx, and esophagus), kidney, stomach, bladder, pancreas, uterine cervix, and blood (e.g., certain leukemias). Exposure to tobacco carcinogens and toxins is also a major cause of other diseases of the pulmonary system (e.g., bronchitis, emphysema, chronic obstructive pulmonary disease), the cardiovascular system (e.g., stroke, atherosclerosis, and myocardial infarction), and the female reproductive system (e.g., increased risk of miscarriage, premature delivery, low birth weight, stillbirth, and infant death). While numerous studies have elucidated some of the chemical and biological properties of cigarette smoke that result in its ability to induce this range of pathologies in the smoker, little is known about the nature and temporal association of molecular events that drive specific stages in the multi-step processes that result in clinically evident disease. This is due, in part, to the limited number of individual tobacco constituents such as benzo[a]pyrene that have been assessed for genetic impact, and the fact that few studies have attempted to address the synergistic relationships between the thousands of individual compounds that constitute the various classes of carcinogens in the vapor and particulate phases of tobacco smoke on gene expression.
Cigarette smoke is primarily a mixture of gases (e.g., nitrogen, oxygen, and carbon dioxide) and suspended particulate material that consists of a wide variety of condensed organic compounds (e.g., 'tar'). This particulate phase contains the majority of compounds [at least 60] for which there is sufficient evidence of carcinogenic potential in animals or human. Presumably, the inherent chemical complexity of cigarette smoke results in an equally complex biological response involving a number of signaling pathways and checkpoints that respond to the direct and indirect stress on the genome in exposed tissues.
There are many available approaches to analyze gene expression after cells are exposed to toxicants. Analysis of gene expression after exposure to cigarette smoke is nontrivial, however, due to the complexity and size of data sets and the fact that technical variation can be introduced at different stages of analysis. Establishing well-specified and carefully validated procedures for standardization and normalization of the data from individual specimens is very important. Selection criteria based on the ratio of measured expression levels fails to account for intra-group variations (e.g., normal biologic variance) and can result in false positive selections, for example. (See Dozmorov et al., J Gerontol A Biol Sci Med Sci 57: B99-108, 2002; Kerr et al., J Comput Biol 7: 819-837, 2000, each of which are expressly incorporated by reference in their entirety).
Many available statistical methods also do not adequately address the mutually exclusive characteristics of sensitivity and specificity. The common practice of using low thresholds for selection of significance (p<0.05) can result in a large number of false positive selections, for example. This is especially problematic for high-density array analysis as the number of false positive selections expected to occur by chance may limit the ability to perform higher order analyses, such as that required to identify molecular pathways that contribute to disease or disease sub-phenotyping, which require the accurate prediction of groups of differentially expressed genes. Attempts to increase stringency by raising the threshold of significance above this value can also be problematic, as it will cause a compensatory decrease in sensitivity and a resultant increase in false negative selections. The use of large numbers of replicates is able improve the analysis, however, this approach is expensive and labor intensive.
Hypervariable analysis (HV), which uses statistical robust delimiters for defining biologically-relevant changes in gene expression, can also be used to analyze cells after exposure to a toxicant. (See Dozmorov et al., Physiol Genomics 12: 239-250, 2003; and Glynne et al., Curr Opin Immunol 12: 210-214, 2000, each of which are expressly incorporated by reference in their entirety). Hypervariable analysis is predicated on the observation that a biologically relevant stimulus will alter gene expression such that homeostasis of the transcriptome is disrupted. Accordingly, these stimuli will modulate the levels of mRNAs of affected genes such that their expression variance over time exceeds the variance observed in the majority of genes in an unstimulated state. Using HV analysis, relatively small biologically relevant changes in gene expression can be identified. Despite current advances in gene expression analysis, there remains a need to identify the genetic events and molecular pathways induced by exposure to tobacco (e.g., cigarette) smoke and tobacco (e.g., cigarette) smoke condensates.

Global gene expression analysis of human bronchial epithelial cells exposed to cigarette smoke, smoke condensates, or components thereof


Described is an optical cable or cable element with a plurality of optical waveguide elements which are stranded together and each consist of several optical waveguides, collected into a bundle, and of a plastic covering surrounding the bundle with a maximum free space of 0.1 mm, and of a non-compressible filling compound filling the intermediate spaces between the optical waveguides, and with a layer of longitudinally aligned glass or plastic fibers surrounding the optical waveguide elements and with an extruded outer jacket of a polymer, the outer jacket compressing the layer radially.

The invention concerns an optical cable or cable element.
Known in the art is an optical cable consisting of a plurality of individual optical waveguides. The optical waveguides are collected into individual optical waveguide bundles, each optical waveguide bundle being surrounded by a plastic covering. Within the plastic covering, in addition to the optical waveguides, is a compound of incompressible material, e.g. petroleum jelly. Several such optical waveguide bundles are stranded together and the stranded assemblage is surrounded by a plastic jacket. Embedded opposite one another within the wall of the plastic jacket are two tensile-stress-and compression-resistant elements (International Wire and Cable Symposium Proceedings 1999, Page 106).
This known cable is distinguished by a high fibre density. Thus, the cable has up to 144 fibers, with a cable outer diameter of 13.5 mm. The two tensile-stress/compression elements present in the cable jacket give the cable a high load capability in respect of tensile stress and compression. A further advantage is that the fibers are easily accessible.
The object of the present invention is to provide for a cable which has the same advantages as the known cable but which has a smaller outer diameter with the same number of fibers or an equal outer diameter with a higher number of fibers.
This object is achieved by the optical cable or cable element with a plurality of optical waveguide elements which are stranded together and each consist of several optical waveguides, collected into a bundle, and of a plastic covering surrounding the bundle with a maximum free space of 0.1 mm, and of a non-compressible filling compound filling the intermediate spaces between the optical waveguides, and with a layer of longitudinally aligned glass or plastic fibers surrounding the optical waveguide elements and with an extruded outer jacket of a polymer, the outer jacket compressing the layer radially.
The essential advantage of the cable according to the invention compared with the known cable lies in the fact that the tensile-stress/compression elements in the wall of the jacket can be omitted. The bending behaviour of the cable is improved substantially as a result. The tensile-stress/compression stability is provided by the layer compressed by the outer jacket. In addition, the compressed layer protects the optical waveguides from transverse forces, which has a positive effect on the transmission characteristics. By comparison with the known cable, a cable diameter reduction of up to 25% is achieved.


An ice chest for a cold plate or drop-in type beverage dispenser wherein the cold plate includes a carbonator integral therewith and the ice chest also includes an aluminum casting as a side wall of the ice bin with prechill cooling coils embedded therein for prechilling the water before it is fed to the carbonator. The cold plate includes a semi-cylindrical sleeve extending downwardly therefrom and forming part of a carbonator housing. The sleeve is in intimate heat exchange contact with both the cold plate and the carbonator for cooling the carbonator.

This invention relates to cold plate (or drop-in) type beverage dispensers.
Cold plate beverage dispensers often are installed with the carbonator located remote from the dispenser. The temperature of the water fed to the carbonator varies during the year, and along with long soda lines to the dispenser causes inconsistent carbonation levels. Installation of such a dispensing system is time consuming, and the long water lines and hook-ups create the potential for leaks.
Cold plate beverages dispensers are well-known. Carbonators used with such dispensers are also well-known. It is known that carbonating efficiency is a function of the temperature of the water; the cooler the water, the higher the carbonation.


An integrated, automated system concerning pharmaceutical products is provided. The system comprises an input queue, a dispensing apparatus comprising a robot device and a number of stations from which the robot device works, and an inspection station. A computer interface provides bi-directional communication between the analytical instruments, robots and peripheral devices and a computer. The robot employed by the system is responsive to computer commands and capable of performing mechanical functions including selection and retrieval of a necessary item and manipulation of retrieved items such that the desired product is produced.

According to the invention there is provided an automated system comprising processing, inspection, and transportation stations for the preparation and delivery of parenteral products to a plurality of stations within a hospital. The system comprises several methods which are currently in the market place. The automated processing of pharmaceutical products via robot devices is not new. Presently employed are robot devices having gripping means presentable to a plurality of stations, each station being adapted to cooperate with the robot device in a sequence of operations such as to produce a measured pharmaceutical dose from a supply of a pharmaceutically acceptable substances, and one of the stations comprising means for locating in parallel a plurality of medical hypodermic syringes for containing a said substance and for operating said syringe. The substance might comprise a medication to be administered to a patient, or a potentially biologically damaging substance, such as a radionuclide or a cytotoxin. The measured dose might be retained in a said syringe, or in a medical vial. Preferably, means are provided for controlling the apparatus in a predetermined sequence of operations.
Sterility is an essential characteristic of injectable and ophthalmic pharmaceutical products. This characteristic is imparted to the product by virtue of the type of manufacturing process. If during the process, all components, solutions and equipment are pre-sterilized and assembled aseptically, that is, using techniques which exclude microorganisms, the product is deemed an "aseptic fill". Other injectable products, in addition to the aseptic processing, undergo sterilization when in the final container, typically using steam under pressure. This procedure, if properly designed and executed, results in a terminally sterilized product.
One solution to the problems incurred through human contamination is through automation of the processing procedure. A paper entitled, "A Robotics System for the Sterility Testing of Injectables," Barbara J. Zlotnick and Michael L. Franklin, Pharmaceutical Technology, May 1987, describes a robotics system for sterility testing of vials. According to this paper a robot is used to perform sterility testing and minimize the manipulations performed by the analyst, thereby reducing the potential for technical contamination attributable to personnel. Since human intervention is minimized during testing, the environment of the test remains cleaner with respect to viable particulate matter. There is a lower level of human activity and less potential for contamination from shedding or from disruption of the laminarity of the air flow under the hood. A cleaner environment can then be used for a greater proportion of the work day.
In general, robotics dispensing devices known in the art include a dispensing apparatus comprising a base, and a robot device on the base. A number of stations are located on the base which cooperate with the robot device in a sequence of operations such as to produce a measured pharmaceutical dose from a supply of pharmaceutically acceptable substances. Robotics dispensing apparatus systems are used for the rapid and efficient processing of a wide variety of pharmaceutical products, as well as perform various mechanical functions. Further, use of the robot device provides an efficient manner in which to maintain a sterile environment to produce the pharmaceutical products.
The transporting of articles via pneumatic tubes is old and well known. Basically, an object is placed within a container which is then transported by air under either positive or negative pressure from one destination to another. The transport is moved within a closed tube. The interior of the closed tube and the outer dimension of the carrier form a seal, so that the carrier can be propelled between the destinations by a vacuum.
In general, pneumatic tube systems known in the art include a closed continuous passageway having a predetermined inner cross-sectional dimension where the passageway includes a plurality of curves or bends having a predetermined radius. A fluid, such as air, is controllably forced through the passageway in a loop to move a carrier through the passageway. In order for the carrier to move freely through the passageway, the dimensions, and in particular the length, of the carriers being used have been limited by the inner cross-sectional dimension and curvature radius of the passageway. Pneumatic delivery systems are used extensively for the rapid and efficient transportation of a wide variety of articles. These delivery systems are used in a number of business operations, including banks, hospitals, office buildings, industrial plants, and truck terminals as a few examples.
One area of commerce which currently uses the pneumatic tube and the transporting of material via the pneumatic tube on a fairly regular basis is the hospital or biomedical research/manufacturing industry. One particular application of this technology is in the area of transporting blood samples, medicines, intravenous bags, viral samples or other biological or chemical matter between locations within a hospital or laboratory.
In that environment, for example, test tubes or vials of liquids are placed within a tube carrier, and are typically secured by foam or clamps within the carrier. The purpose of securing the samples (which are often contained within glass test tubes with rubber stoppers) is to help prevent breakage. When glass breaks or stoppers become dislodged (as can happen when hospital workers fail to properly secure the stoppers in the first place), chemical or biological substances can leak into the interior of the carrier. In turn, said substances can leak out of the interior of the carrier, thereby contaminating the interior walls of the tube system.
The vials or vessels of liquids, solids or gasses within the carrier can move or shift during transport, which can also lead to breakage. This problem is especially acute, as the carriers are often travelling at speeds in excess of 25 feet per second. Because of the rapid acceleration and deceleration of pneumatic tube carriers, the carrier contents can easily become dislodged, and can break within the carrier, if not for clamps, foam securing means, and the like. Nonetheless, accidents can happen, whereby despite the best efforts toward securing or protecting the interior vessels, they can break, or their stoppers can become dislodged. In fact, dislodged stoppers are a primary problem, due mainly to workers who may inadvertently fail to secure them properly in the first place.
If the leaking substance is of a sufficient quantity, the substance (often a fluid) can leak out of the carrier. In that case, the entire tube transport system could become contaminated with the substance. For example, if fluids containing a virus or bacteria sample (for example, the HIV virus or the Ebola bacteria) were to leak out of a carrier, the interior of the vacuum transport tubes could become breeding grounds for the biological specimens—thus contaminating the exteriors of all carriers that pass through the system. Also equally important is that fluids escaping from the carrier can "gum up" the interior of the vacuum tubes, making the smooth passage of the carrier difficult, resulting in enhanced downtime, increased maintenance expense, and increased power consumption (that is, friction would increase within the tube system).
Of course, other problems can result. For example, a hospital worker may cut his or her hands on a broken vial or syringe when they proceed to open the carrier, and dangerous substances contained within the carrier may come in contact with the hospital worker. Also, in the case where toxic, aromatic substances such as toluene or benzene are being transported within vessels contained within the carriers, obviously, the worker would be placed in great danger if he or she opened the carrier under those circumstances. Basically, if a hospital worker opens a carrier expecting to remove sealed vessels and/or containers, and conversely, is presented with spilled contents (which may often be accompanied by broken glass, for example), then, the possibility of infecting the hospital worker or the overall tube system is great. For that reason, a watertight or airtight carrier could facilitate containing the hazardous substances within the carrier, so that vessels that may break or become unsealed in the transport process are contained within the carrier. Of course, problems can still result if workers open a carrier without knowledge of the hazardous circumstances within. To safeguard against that event, the carrier could contain an indicator on its exterior that notifies the carrier handler of the interior circumstances—before the carrier is opened. In that case, if the interior contents are, for example, toxic gasses, the carrier may be opened in a controlled, safe environment.
It is preferable in the present invention to use in the pneumatic tube system a carrier with suitable watertight and airtight properties, such that matter from within the carrier cannot escape to the outside, and matter that has become uncontrollable within the carrier can activate a warning indicator on the exterior of the carrier, so that hospital or other workers who use the carriers will not open carriers with uncontrolled contents (without ample warning that proper measures should be taken). That could be facilitated by a warning signal indicative of a spill or other abnormal condition within the carrier. Such a warning signal may even be a digital output, which can be decoded, to indicate what type of hazard lies within the carrier. Such a warning signal could also trigger a locking mechanism, making the opening of a carrier with spilled interior substances impossible, without authorization and a form of key, electronic or otherwise. Also, based on the contents of the carrier, the locking mechanism may be activated so that only certain parties may be able to open the carrier, regardless of whether an uncontrolled substance is contained within. For example, if a dangerous controlled substance such as morphine is being transported, the carrier may be locked, and only certain authorized persons would be able to open the carrier.
Pneumatic carriers for use in such pneumatic tube systems come in a wide range of sizes and shapes to accommodate the physical articles to be transported in the system. As an example, pneumatic carriers are provided for transporting cash, messages, stock transaction slips, letters, blueprints, electronic data processing cards, x-rays, pharmaceutical supplies, blood samples, narcotics, viral and bacteria cultures, and a variety of other small physical objects.
In the past, various mechanisms have been utilized as closure devices for pneumatic tube carriers. For example, many such carriers include an end cap that is hinged with respect to a cylindrical hull on one side of the hull and which has a latch that fastens the end cap to the opposite side of the hull in a closed position. Such carriers employ a variety of fasteners, such as snap fasteners, elastic straps with holes that fit over hooks, or straps that may be secured to bendable posts.
Other types of pneumatic tube carriers are of the side opening variety. One conventional form of such a carrier employs two generally semi-cylindrical sections that are hinged along one longitudinal edge. The hinged sections may be swung toward or away from each other to effectuate opening and closing of the carrier hull. Locking is achieved by virtue of the end caps, which may be twisted to effectuate threaded engagement of the caps onto the carrier hull ends when the hinged hull sections have been closed. That is, the end caps are rotated in such a fashion as to be drawn towards each other onto the ends of the hull, thereby immobilizing the hull sections relative to each other. Rotation of the end caps in the opposite direction releases the hull sections and allows them to be opened.
One preferable configuration is that of a side opening, wherein the two sides are hinged together, and the two sides are held together when the carrier is closed by use of a hook, or detent or indented type locking lip. Such carriers include latching mechanisms to prevent the door from coming ajar or opening during transit, which could cause the carrier to become lodged in the pneumatic tubes and would also allow the contents of the carrier to spill out into the tube system. In addition, the instructions for latching such side opening containers or carriers are simple to follow, so that the container can be easily placed within the tube system. Such hinging and locking mechanisms make waterproofing or sealing the carrier a particularly difficult task, as the hinges and locks are embedded within the mold of the carrier, which is generally formed of plastic.
In another type of side opening pneumatic carrier, the access to the carrier is gained by simultaneously pulling and twisting the ends of the carrier to allow the side opening door to be opened. The instructions for such a two-step process are often difficult for many users to follow, and the physical effort and manual dexterity needed to simultaneously pull and twist both ends of the carrier against a spring resistance is often troublesome for many hospital workers.
The present invention displays a preference for a pneumatic carrier which can be easily opened, but which also maintains a watertight and airtight seal. Also, the carrier should be able to maintain its air and water tightness, despite the fact that it is subjected to a vacuum transport system, and despite the fact that it will be subjected to extreme environmental conditions, such as repeated use, frequent drops, dust and dirt particles, high speed travel and acceleration, and the like. The carrier should also have a supplemental sensor mechanism to indicate that abnormal interior conditions have developed.

Parenteral products automation system (PPAS)


A fabrication process of a non-volatile semiconductor memory device includes the step of forming a plurality of openings in a device isolation structure defining an active region in a memory cell region such that each opening exposes the substrate surface extends from the active region to the outside thereof. Further, silicide regions are formed in the openings by a self-aligned process such that the silicide regions are mutually separated. Further a contact hole is formed in an interlayer insulation film in correspondence to the silicide regions.

The present application is based on Japanese priority application No. 2000-351444 filed on Nov. 17, 2000, the entire contents of which are hereby incorporated by reference.
This invention relates to semiconductor devices generally. Especially it is related to a non-volatile semiconductor memory and fabrication process thereof.
A flash memory is a non-volatile semiconductor memory that has a simple device structure suitable for high-density integration similar to DRAMs. Thus, it is used in the various information processing apparatuses including computers and cellular phones widely. Generally, a flash memory stores information in a floating gate electrode in the form of electric charges.
Recently, a non-volatile semiconductor memory having a MONOS (metal-oxide-nitride-oxide-semiconductor) structure or SONOS (semiconductor-oxide-nitride-oxide-semiconductor) structure has been proposed. These non-volatile semiconductor memory devices use an insulation film having an ONO structure for the gate insulation film of the MOS transistor and stores information in the ONO gate insulation film in the form of electric charges.
In the non-volatile semiconductor memory of such a MONOS structure or SONOS structure, injection of electric charges into gate insulation film is conducted from a drain side or a source side. As a result, storage of multivalent information becomes possible.
FIG. 1 is a diagram that shows the circuit construction of a NOR/AND type non-volatile semiconductor memory 10 that has a conventional SONOS structure.
FIG. 1 is referred to.
The non-volatile semiconductor memory 10 has a memory cell array M that includes plural memory cell transistors M11-Mmm, each having a gate insulation film of the ONO structure. In the memory cell array M, the memory cell transistors are arranged in a matrix formation. A group of memory cell transistors aligned in a row direction in the memory cell array M are connected commonly to any of the word lines WLn, WLn+1, WLn+2, WLn+3 . . . extending in a row direction at the respective gate electrodes. Furthermore, a group of memory cell transistors that are aligned in a column direction are connected in memory cell array M commonly to any of the data bit lines DBLh+1, DBLh+2, DBLh+3, DBLh+4 that extend in the column direction at the source diffusion region and the drain diffusion region.
Furthermore the non-volatile semiconductor memory 10 has select gate lines SG1,2,3,4, . . . The data bit lines DBLh and DBLh+2 are connected to the corresponding main bit lines MBLh by select transistors T1 and T2 connected to the select gate lines SG1 and SG2. Also, the data bit lines DBLh+1 and DBLh+3 are connected to the corresponding main bit line MBLh+l by select transistors T3 and T4 connected to select gate lines SG3 and SG4.
In, such a construction, information is written into the gate insulation film of the memory cell transistors M11, M12, . . . that has the ONO structure in the form of channel hot-electrons injected from the source region or drain region. The electric charges thus injected are held stably in the ONO film.
FIG. 2 shows the construction of a transistor 20 that constitutes the memory cell transistor M11, M12, . . . in the memory cell array M.
FIG. 2 is referred to.
The transistor 20 is formed of on a Si substrate 21. In the Si substrate 21, there are formed buried diffusion regions 21A and 21B respectively as the source region and drain region. Furthermore the surface of substrate 21 is covered with an ONO film 22 of the structure in which an oxide film 22a, a nitride film 22b and an oxide film 22c are stacked. Further, a polysilicon gate electrode 23 is formed on the ONO film 22.
FIGS. 3A and 3B are diagrams that show the writing operation and the erasing operation carried out in the memory cell transistor of FIG. 2, respectively.
FIG. 3A is referred to.
A source region 21A is grounded at the time of the writing of information and a large positive voltage +Vw is applied to the drain region 21B. Further, a large positive voltage +VG1 is applied to the gate electrode 23. As a result, hot-electrons are formed in the channel as a result of acceleration of electrons at the drain edge of the channel region. The hot-electrons thus formed are then injected into the ONO film 22. The hot electrons thus injected are held in the ONO film 22 in the vicinity of the drain edge. By exchanging the drive voltage that is applied to the drain region 21B and the source region 21A, it is also possible to carry out the injection of the hot electrons similarly in the vicinity of the source edge of the ONO film 22. As represented in FIG. 1, it becomes possible to write 2 bits of information for every one cell in the memory cell transistor 20 of FIG. 2.
When deleting information that is already written, a large positive voltage +Ve is applied to drain region 21B as represented in FIG. 3B. Furthermore a large negative voltage xe2x88x92VG2 is applied to the gate electrode 23. With this, holes are injected from drain region 21B into the ONO film 22. As a result, the electric charges that are accumulated in the vicinity of the drain edge in ONO film 22 are annihilated. In the case the electrons are accumulated in the vicinity of the source edge in ONO film 22, it is sufficient to carry out the hole-injection from source region 21A.
When reading out information written in the vicinity of the drain edge of the ONO film 22, a specified gate voltage Vg is applied to gate electrode 23 as represented in FIG. 4A. Further, the drain region 21B is grounded and the source region 21A is applied with a reading voltage Vr. As a result, it becomes possible for the careers to flow to the source region 21A from the drain region 21B through the channel formed in the Si substrate 21 right underneath the gate electrode 23, provided that electron are not accumulated in the vicinity of the drain edge of the ONO film 22. As a result, the memory cell transistor 20 conducts.
In the case the electrons are accumulated in the vicinity of the drain edge of ONO film 22 on the other hand, the channel right underneath the gate electrode 23 is blocked at the drain edge. Thus, the transistor 20 does not conduct. In the case of reading out the information written in the vicinity of the source edge of the ONO film 22, on the other hand, the source region 21A is grounded as represented in FIGS. 4A and 4B. Further, a read voltage Vr is applied to the drain region 21B.
FIGS. 5A-5D, FIGS. 6A-6C, FIGS. 7A-7D, FIGS. 8A-8C, FIGS. 9A-9D and FIGS. 10A-10C show the fabrication process of a non-volatile semiconductor memory 10 that uses the memory cell transistor 20.
FIGS. 5A-5D are referred to.
FIG. 5A is a plan view of the non-volatile semiconductor memory 10 while FIG. 5B shows the non-volatile semiconductor memory 10 in a cross-sectional view taken along a line X1-X1xe2x80x2 of FIG. 5A. FIG. 5C shows the non-volatile semiconductor memory 10 in a cross-sectional view taken along a line X2-X2xe2x80x2 of FIG. 5A. Further, FIG. 5D shows the non-volatile semiconductor memory 10 in a cross-sectional view of taken along a line X3-X3xe2x80x2 of FIG. 5A.
FIGS. 5A-5D are referred to.
An active region is defined on the Si substrate 21 by a field oxide film 21F having a thickness of 200-500 nm formed by a thermal oxidation processes at 900-1000xc2x0 C. Further, an ONO film 22 is formed on the active region. More specifically, the surface of the Si substrate 21 exposed at the active region is thermally oxidized at 800-1100xc2x0 C. As a result, an oxide film 22a is formed with a thickness of 5-10 nm. Furthermore, a CVD process is conducted at 600-800xc2x0 C. on the oxide film 22a. Thereby, a nitride film 22b is deposited with a thickness of 12-16 nm. Furthermore an oxide film 22c is formed on the nitride film 22b by a wet oxidation processes at 1000xcx9c1100xc2x0 C. with a thickness of 5-10 nm.
In the process of FIG. 5A, a resist pattern R1 is formed on the ONO film 22 thus formed such that the resist pattern R1 has an opening corresponding to each of data bit lines DBL to be formed, and As+ ions are introduced into the Si substrate 21 through the resist opening by an ion implantation process with a dose of 2xc3x971015xcx9c5xc3x971015 cmxe2x88x922 under an accelerating voltage of 50xcx9c90 keV. As a result, a number of n-type diffusion regions 21D corresponding to the data bit lines DBL are formed in the Si substrate 21 in parallel with each other. In the following, the n-type diffusion region 21D will be designated as bit-line diffusion region.
In the state of FIG. 5A-5D, the same cross-sectional structure appears in the cross-sectional view of FIGS. 5B-5D.
FIG. 6A shows the cross-sectional diagram taken along a line Y-Yxe2x80x2 of FIG. 5A, while FIG. 6B shows the cross-sectional diagram of the n-channel peripheral transistor used in the non-volatile semiconductor memory 10. Further, FIG. 6 C shows the cross-sectional diagram of the p-channel peripheral transistor that is used in the non-volatile semiconductor memory 10.
FIG. 6A is referred to.
It can be seen that the bit-line diffusion region 21D extends in the active region defined by the field oxide film 21F in the extending direction of the data bit line DBL continuously. As can be seen in FIGS. 6B and 6C, the p-channel peripheral transistor region and the n-channel peripheral transistor region are covered by a resist pattern R1 in the state of FIG. 5(A). Thus, no ion implantation is caused into the substrate in the state of FIG. 6A into the peripheral transistor region.
Next, the resist pattern R1 is removed in the step of FIGS. 7A-7D, and plural polysilicon gate electrode patterns 23 (referred to hereinafter as word line electrode) are formed on the Si substrate 21 in correspondence to the word line WL of FIG. 1, such that each polysilicon gate electrode patterns 23 extends in a direction generally perpendicular to the extending direction of the diffusion regions 21D.
Furthermore, a channel-stop diffusion region 21d is formed between the bit-line diffusion regions 21D by an ion implantation process of B that introduces B ions into the Si substrate 21. During the ion implantation process, the word line electrode 23 is used as a mask. The ion implantation process may be conducted with a dose of 3xc3x971012-1xc3x971013 cmxe2x88x922 under acceleration voltage of 50-80 eV as shown in FIG. 7B or FIG. 7D. It should be noted that FIG. 7A shows the non-volatile semiconductor memory 10 in a plan view.
Further, it should be noted that FIGS. 7B-7D show the cross-sectional views respectively taken along a line X1-X1xe2x80x2, a line X2-X2xe2x80x2 and a line X3-X3xe2x80x2 of FIG. 7A. As shown in FIG. 7C, the channel-stop diffusion region 21d is not formed right underneath the word line electrode 23. In FIGS. 7B and 7C, the channel-stop diffusion region 21d is formed also in the bit-line diffusion region 21D. In FIGS. 7(B) and 7C, the illustration of the channel-stop diffusion region 21d is omitted because very small impurity concentration level there in.
FIG. 8A shows the cross-sectional diagram of FIG. 7A taken along the line Y-Yxe2x80x2.
FIG. 8A is referred to.
It can be seen that plural word line electrodes 23 are formed repeatedly with a regular interval on the ONO film 22. Also, the channel-stop diffusion region 21d is formed at the edge part of diffusion region 21D as a result of the ion implantation of B.
The ONO film 22 is removed in the step of FIG. 7A by a mask process from the region of the peripheral transistor, after the step of removal of resist pattern R1 but before the step of formation of the word line electrode 23. Furthermore, thermal oxidation processes is conducted at 800-1100xc2x0 C. Thus, a thermal oxide film 22ox is formed typically with a thickness of 5-15 nm as shown in FIGS. 8B and 8C. As the ONO film 22 is already formed in the memory cell region M, formation of new oxide film does not occur even when such a thermal oxidation process is conducted. Furthermore, gate electrodes 23G1 and 23G2 are formed on the thermal oxide film 22ox thus formed simultaneously to the formation of the word line electrode 23, as shown in FIGS. 8B and 8C.
Because the data bit line DBL is provided by the diffusion region 21D in the non-volatile semiconductor memory 10, it is necessary and desirable to decrease the resistance of the bit line. Thus, as shown in FIGS. 9A-9D, an interconnection pattern 24M is provided on the diffusion region 21D in correspondence to the data bit line DBL such that the interconnection pattern 24M extends parallel with the diffusion region 21D. It should be noted that FIG. 9A shows the plan view of the non-volatile semiconductor memory 10. Also, FIGS. 9B-9D show the cross-sectional diagram of FIG. 9A taken along the lines X1-X1xe2x80x2, X2-X2xe2x80x2, and X3-X3xe2x80x2.
FIGS. 9B-9D are referred to.
An interlayer insulation film 25 is formed so as to cover the word line electrode 23 on the Si substrate 21. A contact hole 25A is formed in the interlayer insulation film 25 by a dry etching process so as to expose the diffusion region 21D. Thereby, the metal interconnection pattern on the interlayer insulation film 25 makes a contact with the diffusion region 21D at the contact hole 25A.
As shown in FIGS. 9A and 9C, a contact hole 25B is formed also on the interlayer insulation film 25 so as to expose the word-line electrode 23. Further, an interconnection pattern 24N is formed on the interlayer insulation film 25 in electric connection with the corresponding the word line electrode 23 at the contact hole 25B.
FIG. 10 shows the cross-sectional diagram of FIG. 9A taken along the line Y-Yxe2x80x2.
FIG. 10A is referred to.
Each of the word line electrodes 23 has a sidewall insulation film 23S thereon. The word line electrode 23 makes a contact with the diffusion region 21D through the contact hole 25A at plural locations in the extending direction thereof. When forming such a sidewall insulation film 23S, an insulation film is deposited on the Si substrate 23 so as to cover the word line electrode 23. Next, the insulation film is etched back by an anisotropic etching process that acts perpendicularly to the substrate principal surface. In the n-channel or p-channel peripheral transistor region, on the other hand, the structure of FIGS. 8B and 8C is covered, after formation thereof, by a resist film (not illustrated). Furthermore, a resist opening is formed in the resist film in the process of Figure lOB. By introducing an n-type dopant through such a resist opening by an ion implantation process, an nxe2x88x92-type LDD region 21 is formed in the Si substrate 2 at both lateral sides of the gate electrode 23G1.
Next, the resist film is removed. Furthermore, another resist film (not shown) is formed in the process of FIG. 10C and a p-type dopant is introduced through a resist opening therein by an ion implantation process. Thereby, a pxe2x88x92-type LDD region 21lp is formed at both lateral sides of the gate electrode 23G2.
Furthermore, a sidewall insulation film is formed to the sidewall of the gate electrodes 23G1 and 23G2 simultaneously to the sidewall insulation film 23S formed on the word line electrode 23 after removal of the resist film. Furthermore, a diffusion region 21n of n+-type is formed outside the sidewall insulation film provided on the gate electrode 23G1 in the n-channel peripheral transistor of FIG. 10B, by conducting an ion implantation process.
Further, a diffusion region 21p of p+-type is formed outside the sidewall insulation film of the gate electrode 23G2 in the p-channel peripheral transistor of FIG. 10C.
In the step of FIGS. 10(B) and 10(C), the contact holes 25C and 25D thus formed in the interlayer insulation film 25, which covers the gate electrode 23G1 and 23G2 on the Si substrate 21, expose the diffusion regions 21n and 21p. Thereby, the metal interconnection pattern 24W formed on the interlayer insulation film 25 makes a contact with the diffusion region 21n in such a contact hole. Further, the metal interconnection pattern 24V makes a contact with the diffusion region 21p.
Meanwhile, there exists stringent demand of high speed operation similar to the one imposed to other high-speed semiconductor devices, also in the conventional non-volatile semiconductor memory 10. Because of this, there is a need of reducing the surface contact resistance as much as possible in the word line electrode 23, in the gate electrodes 23G1 and 23G2, and in the surface of the diffusion region 21D or the diffusion regions 21n and 21p.
In the example of FIGS. 11A-11D, the silicide layer 26 is formed on the surface of the Si substrate 21 as shown in FIGS. 11A, 11B and 11D. The contact hole 25A of the interlayer insulation film 25 is formed such that the silicide layer 26 is exposed. Also, the silicide layer 26 is formed on the word line electrode 23. Furthermore, the silicide layer 26 is formed on the surface of substrate 21 along the bitline diffusion region 21D as shown in FIG. 12A, except for the part where the word line electrode 23 is formed. Furthermore, the silicide layer 26 is formed on the surface of the n+-type diffusion region 21n and on the surface of the p+-type diffusion region 21p, as can be seen in FIGS. 12B and 12C.
Such a silicide layer 26 can be formed by using the word line electrode 23 and also the gate electrodes 23G1 and 23G2 as a self-aligned mask in the process of FIGS. 7A-7D or in the process of FIGS. 8A-8C. After removing the ONO film 22 by a pyro-phosphoric acid treatment and a HF treatment, a refractory metal layer of W is deposited. The W layer thus deposited is caused to react with Si of the underlying layer. Especially, as shown in FIGS. 12B and 12C, the contact resistance of the semiconductor device, which is demanded to provide especially high-speed operation, is reduced, by forming the silicide layer 26 on the surface of the diffusion region 26 of the peripheral transistor. Thereby, the problem of signal delay that originates from the contact resistance is effectively reduced.
In the structure of FIGS. 11A-11D or FIGS. 12A-12C, it is very important that the silicide layer 26 is formed in correspondence to the contact hole 25A that is formed in the interlayer insulation film 25 as shown in FIG. 11B or in FIG. 12A. As explained before, the dry etching process that removes the oxide film is performed so as to reduce the contact resistance in the contact holes 25 C and 25D and in the contact hole 25A as represented in FIGS. 12B and 12C. Thus, the dry etching process has to be carried out such that the silicide layer 26 is not etched. In the event the silicide layer 26 is not formed in these regions, the dry etching would invade into the diffusion region 21D and reach the Si substrate 21. When this occurs, the desired device characteristic is no longer obtained.
However, the constitution of FIGS. 11A-11D has a fatal problem in that adjacent diffusion regions 21D easily cause short-circuit via the silicide layer 26 as represented in the cross-sectional diagram of FIG. 11B by *. In the cross-section of FIGS. 11B-11D, the conduction between the adjacent diffusion region 21D has to be caused as a result of the device operation. When this part causes short-circuit, the flash memory does not operate. On the other hand, the silicide layer 26 is indispensable at the contact hole 25A, as explained previously.
FIGS. 13A-13D and FIGS. 14A-14C show an example that is conceivable for overcoming the foregoing problem.
First FIG. 14A is referred to.
In the illustrated structure, the process of forming the sidewall insulation films 23W1 and 23W2 on the gate electrodes 23G1 and 23G2 in the peripheral transistor of FIGS. 14B and 14C is conducted by a deposition and etch back process of the insulation film 23W, wherein the deposition and etch back process is conducted while leaving the insulation film 23W deposited on word line electrode 23 selectively in the memory cell region M. For this purpose, a resist pattern is used.
Furthermore, an opening 23WA is formed in the insulation film 23W in correspondence to the contact hole 25A as represented in FIGS. 13B and 13C, and an opening 23WB is formed in correspondence to the contact hole 25B. Further, the silicide layer 26 is formed on bit-line diffusion region 21D in correspondence to such an opening 23A. Further, the silicide layer 26 is formed on the word line electrode 23 in correspondence to the opening 23B.
According to such constitution, the insulation film 23W exists between a pair of adjacent bit-line diffusion regions 24D. Therefore, no silicide layer 26 that may cause short-circuit is formed between the bit-line diffusion regions 24D.
However, there exists a limit in the patterning precision, and there inevitably appears a limit in the integration density when the non-volatile semiconductor device 10 is to be formed according to such a process in which the silicide layer 26 is formed in the memory cell array M selectively in the openings 23WA and 23WB of the insulation film 23. As explained before, the silicide layer 26 has to be formed positively right underneath the contact holes 25A and 25B in relation to the process of removing the native oxide film by the dry etching process.
Accordingly, it is a general object of the present invention to provide a novel and useful non-volatile semiconductor memory device and the fabrication process wherein the foregoing problems are eliminated.
Another and more specific object of the present invention is to provide a non-volatile semiconductor memory device of SONOS type or MONOS type having a self-aligned silicide layer on a contact region and is capable of eliminating short circuit between diffusion regions positively.
Another object of the present invention is to provide a non-volatile semiconductor device, comprising:
a semiconductor substrate carrying an active region defined by a device isolation structure thereon;
a plurality of diffusion regions formed in said active region with a separation from each other, each of said plurality of diffusion regions extending in a first direction;
a word line electrode extending over said active region in a second direction crossing said first direction; and
a charge storable insulation film formed on said active region in correspondence to said word line electrode between a surface of said active region and said word line electrode, said charge storable insulation film having a stacked structure in which a nitride film and an oxide film are stacked consecutively on an oxide film,
said device isolation structure having a plurality of openings each exposing said surface of said substrate in correspondence to an extension part of said plurality of diffusion regions,
each of said plurality of diffusion regions having said extension part extending into corresponding one of said plurality of openings;
each of said plurality of diffusion regions carrying a silicide film on a surface thereof.
Another object of the present invention is to provide a method of fabricating a non-volatile semiconductor memory device on a semiconductor substrate having a memory cell region and a peripheral circuit region, comprising the steps of:
defining an active region on said memory cell region of said semiconductor substrate by forming a device isolation film;
forming a charge storable insulating film on said active layer;
forming a plurality of bit-line diffusion regions in said active region such that each of said bit-line diffusion region extend parallel with each other in a first direction;
forming a word line electrode on said active region so as to extend in a second direction crossing said first direction and forming simultaneously a gate electrode on said peripheral circuit region of said semiconductor substrate;
forming a sidewall insulation film on both sidewall surfaces of said gate electrode in said peripheral circuit region;
forming first and second diffusion regions in said peripheral circuit region at both sides of said gate electrode while using said gate electrode and said sidewall insulation film as a mask; and
forming a silicide layer on a top surface of said gate electrode and a surface of said first and second diffusion regions,
said step of defining said active region comprising the step of forming a plurality of openings exposing a surface of said semiconductor substrate in said device isolation film along an edge part of said active region, such that said surface of said semiconductor substrate is exposed continuously from said active region to an outside of said active region,
said step of forming said plurality of bitline diffusion regions being conducted such that each of said plurality of bit-line diffusion regions extends continuously from said active region to a corresponding one of said plurality of openings,
said step of forming said sidewall insulation film on said gate electrode comprising the steps of covering said gate electrode and said word line electrode by a common insulation film, and forming said sidewall insulation film by applying an etch back process to said common insulation film selectively in said peripheral circuit region while leaving said common insulation film on said active region,
said method of fabricating said non-volatile semiconductor memory device further comprising the step of forming a silicide layer on a surface of said bit-line diffusion regions extending into respective, corresponding openings,
said step of forming said silicide layer on said bit-line diffusion region conducted simultaneously to said step of forming a silicide layer on a surface of said first and second diffusion regions.
Another object of the present invention is to provide a method of fabricating a non-volatile semiconductor memory device on a semiconductor substrate having a memory cell region and a peripheral circuit region, comprising the steps of:
defining an active region on said memory cell region of said semiconductor substrate by forming a device isolation structure;
forming a charge storable insulation film on said active region;
forming a plurality of bit line diffusion regions in said active region such that each bit line diffusion region extends in a first direction with a separation from each other;
forming a conductor layer on said active region such that said conductor layer covers said active region entirely and simultaneously forming a gate electrode in said peripheral circuit region of said semiconductor substrate;
forming first and second diffusion regions in said peripheral circuit region at both lateral sides of said gate electrode while using said gate electrode and said sidewall insulation film as a mask;
forming a silicide layer on a top surface of said conductor layer and on a top surface of said gate electrode and on a surface of said first and second diffusion regions in said active region and in said peripheral circuit region; and
patterning said conductor layer in said active region to form a word line electrode extending in a second direction crossing said first direction,
said step of defining said active region including the step of forming a plurality of openings in said device isolation structure along an edge of said active region so as to expose a surface of said semiconductor substrate respectively in correspondence to said plurality of bit-line diffusion regions, such that said surface of said semiconductor substrate is exposed continuously form said active region to an outside of said active region,
said step of forming said plurality of bit line diffusion regions comprising the step of forming said bit-line diffusion regions such that each of said bit-line diffusion regions extend continuously from said active region to a corresponding one of said plurality of openings,
said method further comprising the step of forming a silicide layer on a surface of said plurality of bit-line diffusion regions each extending into corresponding one of said openings while using said common insulation film left on said active region as a mask,
said step of forming said silicide layer on said surface of said bit-line diffusion region being simultaneously to said step of forming said silicide layer on said word line electrode and on said first and second diffusion regions.
According to this invention, following advantageous features are obtained when forming a low-resistance silicide layer on the gate electrode or on the surface of the source/drain diffusion regions of the MOS transistor constituting a peripheral circuit of a non-volatile semiconductor memory, in that a silicide layer is positively formed by a self-alignment process in the memory cell region in correspondence to the part extending out from a memory cell region defined by a device isolation structure to the outside of the memory cell transistor. The extending part may be the one used for interconnection with a bit-line electrode pattern provided on an interlayer insulation film via a contact hole. As a result of the present invention, the active region of the memory cell region is positively prevented from being etched even when a dry etching process is applied in the peripheral circuit region as a pre-processing process for removal of native oxide film prior to the step of providing an interconnection pattern to the MOS transistor. As the present invention provides interconnection to the bit-line electrode pattern at a contact hole formed in the interlayer insulation film in correspondence to a device isolation region, the problem of short-circuit does not occur between the silicide layers that are formed in correspondence to respective bit-line diffusion regions.
In the non-volatile semiconductor memory device of this invention, it is desirable to form a silicide film on the surface of the diffusion region and further on gate electrode constituting the peripheral circuit region. Further, it is desirable to form the charge-accumulating insulation film so as to cover the entire surface of the active region continuously. Furthermore, there may be an insulation film formed so as to cover the surface and the sidewall surface of the word line electrode and the exposed substrate surface continuously. In this case, it is preferable that the insulation film covers the word line electrode in conformity with a shape thereof with a uniform thickness. Further, the insulation film covers the entire surface of the active region continuously. It is desirable that the interlayer insulation film covers the insulation film. Also, it is desirable that a silicide film is formed in the extending part of the word line electrode that extends outside the active region. It is desirable to form, in the interlayer insulation film, another contact hole outside the active region so as to expose the outside part. The silicide film may be formed on the word line electrode over the entire length thereof. In doing so, it is possible to form a sidewall insulation film on the extending part of the word line electrode extending the to the outside of the active region so that the sidewall insulation film encloses the active region. Such a sidewall insulation film composes a part of the insulating wall that towers from the substrate in a direction generally perpendicular to the substrate principal surface. In this invention the word line electrode can be formed of a conductive semiconductor material.
According to this invention, it becomes possible to form a silicide layer in a Si surface by a self aligned process in any of a memory cell region and a peripheral circuit region of a non-volatile semiconductor device having a charge storable insulation film. Thus, the problem of etching or attacking of the Si surface does not occur even when removal of natural oxide film is conducted by a dry etching at the time of forming a contact is formed on the Si surface, and deterioration of the device performance is successfully avoided. As a result of formation of the silicide layer, the non-volatile semiconductor memory of this invention has a preferable feature of reduced contact resistance. Thus, the non-volatile semiconductor device operates at high speed.
Other objects and further features of the present invention will become apparent from the following detailed description when read in conjunction with the attached drawings.

Non-volatile semiconductor memory device and fabrication process thereof