A narrow magnetic body 66 in which outward path and inward path recording magnetic head devices 1WF and 1WR, capable of recording at least data on a metal evaporated type magnetic tape 51 running in the outward and inward direction and vice versa along the longitudinal direction, comprise the operation magnetic gaps GF and GR with the asymmetric structure is located at the leading side of the metal evaporated type magnetic tape 51. With this arrangement, magnetic field influence exerted by the narrow magnetic body can be decreased, and difference produced between magnetic recording and reproducing characteristics when the metal evaporated type magnetic tape is transported in the outward direction and in the inward direction can be decreased. Also, deteriorations of characteristics deteriorated by off-track upon reproduction can be improved. Thus, when the recording magnetic heads with the operation magnetic gaps having the asymmetric structure are in use and the metal evaporated type magnetic tape is transported in the outward and inward direction and vice versa, difference produced between magnetic recording and reproducing characteristics when the metal evaporated type magnetic tape is transported in the outward and inward direction and vice versa can be decreased. Also, deteriorations of characteristics deteriorated by off-track upon reproduction can be improved.

1. Filed of the Invention
The present invention relates to a magnetic head apparatus using a metal evaporated type magnetic tape and a drive apparatus including a magnetic head apparatus.
2. Description of the Related Art
In recent years, in accordance with an explosive increase of a data amount, the increase of a storage capacity becomes the most urgent need in a tape-system storage system, and hence it is requested to increase a recording density to realize the above-mentioned increase of the storage capacity.
Under such circumstances, there is a trend that a so-called linear type magnetic recording tape system in which a magnetic tape is transported in the outward and inward direction and vice versa relative to a magnetic tape so as to record thereon data in a serpentine fashion is widely used increasingly.
However, in a magnetic tape formed of a coating type magnetic layer and which is now commercially available on the market, the increase of the recording density seems to reach its limit, and under the present circumstances, it cannot be expected that recording density will not be increased more than the present high recording density. For this reason, also in the linear type magnetic recording tape system, it has been discussed to use a so-called metal evaporated type magnetic tape for use in high recording density and if which magnetic layer is formed of a ferromagnetic metal evaporated film.
However, in the metal evaporated magnetic tape, its recording and reproducing characteristics become different depending upon the sliding direction in which a magnetic tape is slidably transported on a magnetic tape. The reason for this is that, since the magnetic layer is formed by rhombic vapor deposition of ferromagnetic metal, the magnetic layer has a rhombic pyramid structure to exhibit rhombic magnetic anisotropy.
So far there have been proposed metal evaporated type magnetic tapes in which difference between recording and reproducing characteristics in accordance with the sliding direction, that is, polarity can be improved (for example, see cited patent references 1, 2 and 3).
In these previously proposed metal evaporated type magnetic tapes, difference between recording and reproducing characteristics relative to the sliding direction can be improved by selecting factors of the magnetic layer, such as structure, film thickness and magnetic properties.
[Cited patent reference 1]: Official gazette of Japanese laid-open patent application No. 4-353621
[Cited patent reference 2]: Official gazette of Japanese laid-open patent application No. 4-353622
[Cited patent reference 3]: Official gazette of Japanese laid-open patent application No. 5-182168
In the linear type magnetic recording tape system, in order to increase the recording capacity more and to realize the higher recording density, it is requested to narrow the width of the recording track more. Concurrently therewith, it is requested to narrow the track width of the operation magnetic gap of the magnetic head. From these requests, as a recording magnetic head, there is used a thin film recording head having a microminiaturized structure that can be manufactured by a thin film technology in the semiconductor manufacturing technology.
In this thin film magnetic head, at least one of upper and lower magnetic cores comprising the operation magnetic gaps at their front portions is composed of a thin film magnetic layer, and the front portion comprising the operation magnetic gap of only one of the magnetic cores composed of the thin film magnetic layers is selected so as to have a narrow width having a target track width. In this manner, the magnetic core having the narrow front portion and the magnetic core having the wide front portion are opposed to each other to construct the operation magnetic gap, and the track width of the operation magnetic gap is determined by the narrow front portion. In the thin film magnetic head of this kind, while its operation magnetic gap has an asymmetric structure relative to the center surface, the track width is determined by the thin film magnetic layer processed with high accuracy and hence the track width of the operation magnetic gap can be microminiaturized with high accuracy.
Since the thin film recording head is manufactured with application of the thin film pattern technology used in the semiconductor manufacturing process as described above, a recording track width is accurate and it has less dispersions. Therefore, as compared with a conventional MIG (Metal in Gap) type magnetic head, this thin film magnetic head has an advantage such that it is suitable for the application to high-density tape systems such as a narrow track multi-channel linear system.
However, when data is recorded on the magnetic tape by the thin film head with the operation magnetic gap having the asymmetric structure as described above, complex magnetic fields are generated in the edge portion of the track width direction. Also, as mentioned hereinbefore, since the metal evaporated type magnetic tape has the rhombic anisotropy, when data is recorded on this magnetic tape, recording and reproducing characteristics of the thin film magnetic head and the metal evaporated type magnetic tape are inevitably changed so much during the magnetic tape is being transported in the outward and inward direction and vice versa.
Further, when data is recorded on the metal evaporated magnetic tape by the thin film magnetic head with the operation magnetic gap having the asymmetric structure, a problem arises, in which an S/N (signal-to-noise ratio) is considerably lowered by off-track in which the thin film magnetic head is shifted from the center of the track upon reproduction.

Magnetic head apparatus and drive apparatus including magnetic head apparatus


A digital camera is disclosed. In an embodiment, the digital camera has an imaging unit including an image sensor and imaging optics and a digital image processor connected to receive raw digital images from the imaging unit and to process the raw digital images. The digital camera also includes a memory configured to store digital image data that has been processed by the digital image processor and a processor configured to direct retrieval of the digital image data that is stored in the memory and the digital image processor is further configured to generate control signals for use in operation of the imaging unit.

1. Field of the Invention
The present invention generally relates to digital cameras. More particularly, improved digital camera architectures and components are described.
2. Description of the Related Art
Recently, digital cameras have become very popular. The digital camera converts an optical image to electronic image data and digitally records the image data on a storage medium. When the image is reproduced, the recorded digital data is retrieved from the storage medium and displayed on a display device or printed out as a hard copy image.
Referring initially to FIG. 1, conventional digital camera systems 100 typically include a digital camera 102 having an optical lens 104 for focusing light rays onto an imaging capture unit 106. The imaging capture unit 106 typically relies upon an array of light sensitive photo optic cells 108, capable of converting the light rays received from the optical lens 104 into representative analog signals. Most commonly, the photo optic cells take the form of charge-coupled devices (CCDs), although other devices such as CMOS receptors may be used as well. As is well known in the art, each CCD array 108 must have associated with it a specific color filter array (CFA). In most applications, the CFA is an empirically derived pattern of individual color filters each associated with a specific CCD cell in the CCO array. A color converter circuit 110 then uses a particular interpolation algorithm associated with the specific CFA to generate the analog signals representing the CCD manufacturer's predetermined concept of the proper color scheme of the image. Manual input controls 103 (i.e., push-buttons, for example) provide manual inputs to a step controller 105 suitably disposed to provide control signals to the imaging capture unit 106. Such control signals are used to control such imaging parameters as f-stop, exposure, zoom, focus, and flash attachments, if appropriate.
The imaging capture unit 106 sends the analog signals representing the image first to an analog-to-digital (A/D) converter unit 112. The A/D converter unit 112 converts the representative analog signals into digital signals representative of the image. The digital signals are then passed to a digital signal processor (DSP) 114 where they are converted to appropriate digital formats. An image compression circuit 116 as well as a memory 118 both receive the appropriately formatted digital signals. The image compression circuit 116 operates to digitally compress the received digital images in order to reduce the amount of resources required to further process the digital signals. One such fom latting scheme referred to as JPEG is commonly used, although there are a wide variety of suitable picture formats. Once the image has been digitally compressed, it is sent by way of a memory interface 120 to a memory slot 122 capable of receiving a memory card 124 suitable for storing the compressed digital signals. Such memory cards 124 include "floppy" disks, flash EPROM cards, R/W compact disc (CD), SmartMedia and the like.
Unfortunately, conventional digital cameras have several important limitations. One such limitation is the fact that the conventional digital camera may only use the color filter array (CFA) and its associated color interpolation algorithms. Any subsequent improvements in CCD array technology cannot easily be incorporated into the conventional digital camera system.
Lack of integration also provides for expensive and cumbersome digital cameras. As can be readily seen, the conventional digital camera system 100 has many discrete functional blocks encompassing many different circuits. It is therefore relatively expensive for conventional digital cameras to provide image correction, color correction, image compression, as well as provide all appropriate control and timing signals in one unit.
In addition, each CCD or CMOS imager has different clocking requirements, resolution, etc. That requires dedicated ASICs, or other dedicated logic, to properly drive them. This results in higher manufacturing cost and an inflexible camera architecture.
It would be advantageous and therefore desirable to have available components that can be used by a variety of digital camera manufacturers, regardless of their specific image sensor, color interpolation scheme, etc.

Digital image processor for a digital camera

Avago Technologies General IP (Singapore) Pte. Ltd.


A method includes obtaining, using at least one processor, an input image frame. The method also includes identifying, using the at least one processor, one or more regions of the input image frame containing redundant information. In addition, the method includes performing, using the at least one processor, an image processing task using the input image frame. The image processing task is guided based on the one or more identified regions of the input image frame. The method may further include obtaining, using the at least one processor, a coarse depth map associated with the input image frame. Performing the image processing task may include refining the coarse depth map to produce a refined depth map, where the refining of the coarse depth map is guided based on the one or more identified regions of the input image frame.

Many mobile electronic devices, such as smartphones and tablet computers, include cameras that can be used to capture still and video images. In many of these mobile electronic devices, multiple types of image processing operations can be performed using captured images of scenes. Many image processing operations use input image frames as guidance for the image processing operations. This means that at least part of an image processing operation can be guided or directed based on certain contents of an input image frame.

Guided backpropagation-gradient updating for image processing task using redundant information from image


An inflatable product includes an inflatable body with a recess. A pump matching the recess is installed in the recess. Whereby, the inflatable body and pump are integrated together, and it is very convenient to use and carry. Furthermore, the pump is concealed in the inflatable product, giving the inflatable product an attractive appearance.

1. Field of the Invention
The present invention relates to an inflatable product, and more particularly to an inflatable product with an integrated pump.
2. Description of Related Art
Inflatable products such as balloons, buoys, and air mattresses need to be inflated for use and deflated for storage. A separate external pump is generally used for inflating/deflating. Thus, it is inconvenient to use and store an inflatable product and a pump.
Therefore, the invention provides an inflatable product with an integrated pump to mitigate or obviate the aforementioned problems.

Inflatable product with an integrated pump


Disclosed is an apparatus for controlling a combustion condition of an internal combustion engine having a plurality of combustion cylinders. The combustion condition of the engine can be detected sensitively by the minimum number of combustion condition sensors, and a control of the combustion condition in each combustion cylinder can be effected on the basis of the output signals from the minimum number of combustion condition sensors. In the present invention, an operating condition of the engine and combustion condition in the predetermined group of combustion cylinders including at least one combustion cylinder are detected and then, a combustion condition control parameter, such as an ignition timing or fuel injection amount of each combustion cylinder, is controlled in accordance with both the detected operating condition and the combustion condition so as to generate an optimum combustion condition in the combustion cylinders of the engine.

1. Field of the Invention
The present invention relates to an apparatus for controlling a combustion condition in an internal combustion engine having a plurality of combustion cylinders.
2. Description of the Related Art
Known in the prior art is an apparatus for controlling a combustion condition in an internal combustion engine having a plurality of combustion cylinders wherein one or more combustion condition control parameters, such as ignition timing, air-fuel ratio of an air-fuel mixture to be fed into the engine cylinders, or supercharging pressure, are controlled to prevent the generation of knocking in the combustion cylinders when a knocking generated in each engine cylinder is detected by a knocking sensor, such an internal pressure sensor for detecting changes in the internal pressure of the combustion cylinder. For example, Japanese Unexamined Patent Public Disclosure No. 61-215942 discloses a control apparatus comprising internal pressure sensors arranged on combustion cylinders, respectively. In such a kind of apparatus, knocking generated in each combustion cylinder is detected by the corresponding internal pressure sensor, and then ignition timing of each combustion cylinder is controlled in accordance with the output signal from the corresponding internal pressure sensor so as to obtain a critical timing for preventing the generation of knocking. That is, in such a known control apparatus, control of the ignition timing of one combustion cylinder is effected in accordance with the output signal from the corresponding internal pressure sensor.
Such a known control apparatus can detect the generation of knocking with high sensitivity, since the internal pressure sensor can directly detect changes of the internal pressure in the corresponding combustion cylinder. However, in such a known control apparatus, each combustion cylinder requires a corresponding internal pressure sensor and therefore, processing of the signals output from the internal pressure sensors becomes complex and so, it makes the expenses of production of the apparatus costly.

Apparatus for controlling combustion condition


A method of forming droplets comprises flowing a liquid through a channel; spreading the liquid into a thin film in the channel; and impinging the thin film with a flowing gas to atomize the liquid into droplets. The droplets may then be dried to produce dried particles, such as particles comprising a pharmaceutical active agent. The droplets formed by the disclosed process have improved size and/or size distribution characteristics.

The ability to accurately and reproducibly produce particles having a well defined particle size and particle size distribution from a liquid feed stock has application in a variety of fields, including food, chemicals, and pharmaceuticals. Such control of particle size and particle size distribution is particularly important in pharmaceutical applications where liquid or dry powder particles containing an active agent are administered to a patient. Controlling the particle size and particle size distribution is desirable in such applications in order to achieve delivery of such particles in a known and repeatable manner.
Powders for pharmaceutical drug administration have been made by spray drying. Spray drying is a conventional chemical processing unit operation used in the chemical, food, and pharmaceutical industries to produce dry particulate solids from a variety of liquid and slurry materials. The process involves rapidly transforming a liquid feed into a dried particulate form by atomizing the feed into a hot drying medium.
Conventional spray drying systems and processes have been disclosed. For example, U.S. Pat. Nos. 5,260,306, 4,590,206, GB 2,105,189, and EP 072 046 describe a method for spray drying nedocromil sodium to form small particles preferably in the range from 2-15 mm for pulmonary delivery. U.S. Pat. No. 5,376,386 describes the preparation of particulate polysaccharide carriers for pulmonary drug delivery, where the carriers comprise particles sized from 5-100 mm and having a rugosity of less than 1.75. WO 96/09814 discloses spray-dried smooth and spherical microparticles which either carry a therapeutic or diagnostic agent. U.S. Pat. No. 6,022,525 discloses microcapsules prepared by spray-drying and which are useful for ultrasonic imaging. Additionally, aerodynamically light particles for pulmonary delivery and particles incorporating surfactants for pulmonary drug delivery and their preparation are disclosed in U.S. Pat. Nos. 5,855,913 and 5,874,064. The spray drying of hydrophobic drugs and excipients is disclosed in U.S. Pat. Nos. 5,976,574, 5,985,248, 6,001,336, and 6,077,543. U.S. Provisional Patent Application 60/222,067 filed on Aug. 1, 2000 discloses a spray drying process that can be tailored to produce substantially monodisperse particles or multimodal particles having well defined and controllable particle size distributions. Additional spray drying processes are disclosed in EP 1004349, WO 96/32149, WO 99/16419, and U.S. Pat. Nos. 6,000,241, and 6,051,256, and in The Spray Drying Handbook, K. Masters. All of the aforementioned references are incorporated herein by reference in their entireties. Various atomizers have been used in the spray drying of pharmaceutical powders. These include gas assisted two fluid nozzles, rotary atomizers and ultrasonic atomizers comprising an oscillating horn to create surface instabilities resulting in droplet formation. Examples of each of these various atomizers are disclosed in the patents cited above. Droplet size and droplet size distribution are affected by the selection of the atomizer.
The application of conventional spray drying technology to the field of pulmonary drug administration presents many technical challenges. For example, there are often particular sizing requirements necessary to administer resultant particles to the deep lung. For pulmonary applications, the aerodynamic size of the particles dispersed in an aerosol directly impacts the deposition pattern in the lung. The major factors influencing this final particle size include the initial liquid drop size, the initial solids concentration, and the drying rate. It is advantageous to create small liquid droplets with the highest solids concentration feasible for a particular process to minimize capital equipment and operating costs.
It can be difficult to achieve a desired low moisture content required for physical and chemical stability in the final particulate product, particularly in an economic manner. Finally, it has proven to be difficult to produce the small particles necessary for some pharmaceutical applications, such as pulmonary delivery, in an efficient manner on a large scale suitable for commercial applications.
Therefore, it is desirable to be able to produce spray dried particles in an improved manner. It is further desirable to be able to produce spray dried particles within a narrow size distribution, in particular for pulmonary drug administration. It is further desirable to be able to generate desired particles in an economic manner.

This patent is subject to a terminal disclaimer.


The present invention relates to an emergency position indicating radio beacon (EPIRB) terminal for confirming positions of ships and rescuing the ships during a marine disaster in a marine search and rescue system and an apparatus and a method for monitoring an operating state of the EPIRB terminal. The EPIRB terminal comprises: a sensor unit for sensing the sinking of a ship in which the EPIRB terminal is provided; a generation unit for generating a distress message corresponding to the sensed result of the sensor unit; and a transmission unit for broadcasting a distress signal including the distress message. The sensor unit comprises: a water-pressure sensor for outputting a water-pressure detection signal by sensing the water pressure in the inside of the ship; a moisture sensor for outputting a moisture detection signal by sensing the moisture inside the ship; and a separation sensor for outputting a separation detection signal by sensing the separation of the EPIRB terminal from the ship. The sensor unit outputs a generating request signal of the distress message to the generation unit by normally sensing the sinking of the ship when the water-pressure detection signal, the moisture detection signal, and the separation detection signal are outputted.

In general, in a maritime search and rescue system, an EPIRB device used for position identification and rescue of a vessel in the event of maritime disaster includes an EPIRB terminal and a housing for installing the EPIRB terminal in a vessel, for example, a container. The EPIRB terminal is installed in the vessel through the housing. Before the vessel sinks under the sea and reaches a predetermined depth of water, for example, 4 m under the sea, the housing is automatically separated from the vessel or container and rises to the surface of the water. The EPIRB terminal transmits a distress signal to a satellite, for example, a COSPAS-SARSAT satellite, at a predetermined period.
The COSPAS-SARSAT satellite receives the distress signal from the EPIRB terminal, and transmits the received distress signal to a local terminal located in a region nearest to the EPIRB terminal, for example, a Local User Terminal (LUT). The LUT calculates and estimate the distress position of the vessel equipped with the EPIRB terminal, and transmits the distress signal to a Mission Control Center (MCC) of a corresponding area. The MCC identifies the position of the distressed vessel through the distress signal, and rescues the distressed vessel.
As described above, in the EPIRB device, the EPIRB terminal is installed in the vessel by the housing, and the EPIRB terminal is separated from the vessel by the sensing operation of sensors included in the EPIRB terminal, for example, a water pressure sensor and a water sensor, rises to the surface of the water, and automatically broadcasts the distress signal. At this time, the water pressure sensor and the water sensor perform the sensing operation when the EPIRB terminal enters the water. However, in a case in which water penetrates into the EPIRB terminal due to various environmental factors in the vessel equipped with the EPIRB terminal and on the sea, the water pressure sensor and the water sensor may malfunction.
Even when the water pressure sensor and the water sensor included in the EPIRB terminal malfunction, the EPIRB terminal broadcasts the distress signal, and the COSPAS-SARSAT satellite receives the distress signal from the EPIRB terminal, and transmits the received distress signal to the LUT located in a region nearest to the EPIRB terminal, the LUT calculates and estimate the distress position of the vessel equipped with the EPIRB terminal, and transmits the distress signal to the MCC of the corresponding area, and the MCC identifies the position of the distressed vessel through the distress signal, and rescues the distressed vessel.
In other words, the maritime search and rescue system normally performs the maritime search and rescue operation, without regard to the malfunction of the water pressure sensor and the water sensor included in the EPIRB terminal. In particular, a lot of resources are wasted by the wrong transmission of the distress signal caused by the malfunction of the EPIRB terminal. For example, according to the announcement of the COSPAS-SARSAT Secretariat in 2009, it was confirmed that about 96% of the distress signals broadcast from the EPIRB terminals was wrongly transmitted, and thus, a lot of resources was being wasted globally.
Therefore, there is a need for minimizing the malfunction of the EPIRB terminal in the maritime search and rescue system and the wrong transmission of the distress signal caused by the malfunction of the EPIRB terminal.

Emergency position indicating radio beacon terminal and apparatus and method for monitoring operating state thereof

ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE


A home WAP gateway system is disclosed that provides user selectable access from digital cordless telephone handsets adapted to WAP communications to services of a local home WAP gateway or to services of a remote WAP gateway in a public network. By a switching means responsive to a message from a handset comprising switching information, the system provides a communication path between a communicating handset and a home WAP gateway when the switching information specifies a predefined home WAP gateway path or between a communicating handset and a public or private telephone network when the switching information specifies a different path.

The invention relates to the field of wireless data communication, and particularly a system based on digital wireless telephone systems technology such as the standardised Digital Enhanced Cordless Telecommunication (DECT) and operating according to the Wireless Application Protocol (WAP) for providing access to local data applications and data files on a private xe2x80x9chomexe2x80x9d WAP gateway.
Without getting as much attention as cellular phones, cordless telephones (CT) are becoming widespread consumer products, and they are paving the way towards ubiquitous low cost personal communications networks. The cordless telephone systems were first manufactured and made commercially available in 1980s. They operate solely as an extension telephones to a transceiver connected to a subscriber line on the public telephone network (PTN) and are primarily for in-home use. They enhance fixed telephones by offering more freedom and higher mobility degree, i.e. allowing the user to operate in a wider area. Cordless telephone systems are generally full duplex communication systems that use radio to connect a portable handset to a dedicated base station, which is then connected to a telephone line associated with a specific telephone number on the public telephone network (PTN). In the first generation, the portable unit communicates only to the dedicated base unit and only over distances of a few tens of meters. Cordless telephone systems provide the user with limited range and mobility, as it is usually not possible to maintain a call if the user travels outside the range of the base station. Typical second generation base stations provide coverage ranges up to a few hundred meters. FIG. 1 illustrates a typical state-of-the-art cordless telephone system.
CT2 is a digital version of the first generation, analogue cordless telephones, introduced in Great Britain. When compared with analogue cordless phones, CT2 offers good speed quality, is more resistant to interference, noise, and fading, and like other personal telephones, uses a compact handset with built-in antenna. The Digital European Cordless Telephone (DECT), later renamed to Digital Enhanced Cordless Telecommunication, is a universal cordless telephone Standard developed by the European Telecommunications Standards Institute (ETSI), issued in 1992.
The Problem Areas
Although digital cordless telephone standards such as DECT specify both voice and data applications, they are limited to the bearer level, that is the ISO-OSI physical and data link layers (layers 1 and 2) and are not sufficient to enable data applications on the handset (or portable unit).
Known Solutions and Problems with These
Generally, existing cordless telephone systems on the market allow only voice communication services on the handsets. Such a limitation is expected soon to be intolerable by the market now that the WAP enabled cellular phones are being launched. The need for a solution enabling access to data and applications both on the world wide web and locally on a PC or workstation via cordless telephone is getting more and more urgent. With the advent of the Internet and the arrival of new generation of handsets having larger displays, the demand for data applications for cordless telephone systems is imminent.
There are some activities in the xe2x80x9cWAP Forumxe2x80x9d aiming to define DECT as an access technology enabling WAP, and to specify how to implement it. A description in this regard is given in the document xe2x80x9cCR to WAPxe2x80x9d of May 29, 1999, Change Request to WAP Forum Ltd, San Francisco, by Arjan te Marvelde, Ericsson, and Dr. G. Kelnhofer, Siemens. However, these activities have focus on the protocol level, i.e. how should the protocol stacks be for different units (handset, Fixed part, WAP gateway, etc.). The main architecture for WAP over DECT is the standard WAP architecture where the public WAP gateway is own and administered by a network operator or a service provider. Such a WAP gateway will also serve a number of users having subscription to the network operator or service provider. As shown in FIG. 2, in the xe2x80x9cWAP over DECTxe2x80x9d architecture the user via his DECT handset can have access to a WEB/WAP server via a public WAP gateway. Such a solution will allow the DECT users to access data and applications residing on remote computers or servers which are in the World Wide Web. However, the architecture does not give direct local access to data and applications residing on a local PC or workstation.
At present the applicant is not aware of any solution that enables access to both data and applications on the web and those residing on a local PC or workstation via cordless telephone handsets.
It is an object of the present invention to extend the xe2x80x9cWAP over DECTxe2x80x9d architecture and thereby allow access from cordless telephone handsets to data and applications on the web as well as those residing on a local PC or workstation.
It is a further object of the present invention to propose a way to obviate the limitation in current cordless telephone systems and to enable all data application types, ranging from Web content access to management of the cordless telephone system itself by means of the Wireless Application Protocol (WAP).
In order to enable data applications on digital cordless telephone systems which can be CT2, DECT or others, this invention promotes the introduction of the Wireless Application Protocol (WAP) in a single base station cordless telephone system. The invention proposes a new architecture for home WAP where a PC-based private WAP gateway is introduced. The private WAP gateway may be owned and administered by the user or user organisation as in the case of a small office or a private home. Such a private WAP gateway allows the user to have access to data applications located locally in his PC as well as those residing on a WEB/WAP server on the Internet.
The objects of the invention are met by a system comprising at least one local PC or similar computer device serving as a local WAP gateway, at least one DECT bases station, and one or more DECT handsets adapted to wireless communication with said at least one base station, wherein the DECT base station is connected to the local WAP server and optionally to a public communications network, the system further comprising a switching function for routing information traffic between the DECT handset and the selected WAP gateway.


A semiconductor memory device includes memory cell blocks having physical pages coupled to memory cells, peripheral circuits configured to program the memory cells or read data stored in the memory cells, and a controller configured to control the peripheral circuits so that a pre-program is performed to make memory cells in the memory cell blocks have threshold voltages higher than a set voltage by programming memory cells of the selected memory cell block, having threshold voltages lower than the set voltage, in response to an erase command. The set voltage is an intermediate threshold voltage obtained from the threshold voltages of the memory cells of the selected memory cell block.

Exemplary embodiments relate to a semiconductor memory device and a method of erasing the same.
There is an increasing demand for semiconductor memory devices which can be electrically programmed and erased and can retain data even without the supply of power. In order to develop high-capacity memory devices capable of storing a large amount of data, technologies for the high integration of memory cells are being researched. To this end, there has been proposed a NAND type memory device including a plurality of memory blocks, each having a plurality of strings. Each of the strings have memory cells coupled thereto in series.
The semiconductor memory device performs an erase operation for erasing data on a memory-cell-block basis.
In the erase operation, the memory cells of the memory cell block have various threshold voltages. In particular, when the memory cells are multi-level cells (MLCs), the threshold voltages of the memory cells have 4, 8, or more threshold voltage distributions. Consequently, there is a great difference between a low threshold voltage and a high threshold voltage.
Accordingly, if the erase operation is performed on a memory-cell-block basis with memory cells having various threshold voltages, the threshold voltages of the memory cells are widely distributed at 0 V or less.
If the threshold voltages of the memory cells having the erase state (referred to as "erase cells") have a wide distribution width at 0V or less, threshold voltages of memory cells in a subsequent data program operation are also likely to have a wide distribution width. In order to prevent this occurrence, it is important that the threshold voltages of the erase cells having 0 V or less are made to have a narrow threshold voltage distribution close to 0 V.
To this end, a pre-program is performed on a memory cell block including MLCs before the erase operation is performed.
The pre-program is performed so that the threshold voltages of all memory cells belong to the highest threshold voltage distribution. If the erase operation is performed in the state in which the threshold voltages of the memory cells belong to the highest threshold voltage distribution, relevant erase cells may have a narrow threshold voltage distribution.
In the conventional pre-program, however, memory cells having high threshold voltages have higher threshold voltages because all the memory cells are programmed at the same time. Consequently, efficiency to place erase cells within a narrow threshold voltage distribution through the pre-program may be reduced.

Semiconductor memory device and method of erasing the same


An ink-jet apparatus includes an ink supply flow path, an ink discharge flow path, and an ink flow path connecting them, in which piezoelectric elements are provided in the ink flow path having at least one turn part, the piezoelectric elements are arranged to be opposed to the ink flow path and are provided upstream of the turn part in the ink flow path and downstream of the turn part in the ink flow path, and a nozzle is provided between the piezoelectric element and the turn part in the ink flow path.

1. Technical Field
The present technical field relates to an ink-jet apparatus.
2. Description of the Related Art
An ink-jet apparatus has a head capable of applying a required amount of ink to an object at given timing in response to an input signal. Especially, a piezoelectric ink-jet apparatus has been positively developed because various kinds of ink can be applied while being controlled with high precision.
In general, the piezoelectric ink-jet apparatus includes an ink supply flow path, an ink flow path connected to the ink supply flow path and having a nozzle, and a piezoelectric element to apply a pressure to ink supplied into the ink flow path. Thus, mechanical strain is generated in the piezoelectric element by applying a drive voltage to the piezoelectric element, and the ink is ejected from the nozzle by applying a pressure to the ink in the ink flow path. In addition, a space in which the ink is collected is called an ink chamber or a pressure chamber provided in the ink flow path.
For example, a configuration of a representative ink-jet apparatus is provided such that the piezoelectric element is arranged on a wall surface of the pressure chamber provided upstream of an ejection hole, and the wall surface of the pressure chamber is pressed by driving the piezoelectric element and a pressure is applied to the ink filled in the pressure chamber, whereby the ink is ejected from the ejection hole (refer to FIG. 1 of Unexamined Japanese Patent Publication No. 2001-121693. In addition, FIG. 1 of Unexamined Japanese Patent Publication No. 60-217160 discloses an ink-jet head provided such that electrostrictive element 4 is arranged in a part of ink supply path 11, and ink is ejected from nozzle 9. In addition, ink-jet apparatuses are disclosed in Unexamined Japanese Patent Publication No. 2007-175921, Japanese Translation of PCT Publication No. 2006-510506, Unexamined Japanese Patent Publication No. 2004-259865, Unexamined Japanese Patent Publication No. 2001-347660, U.S. Patent Publication No. 2006/0227179, U.S. Pat. No. 6,450,627, U.S. Pat. No. 7,157,837, and U.S. Pat. No. 7,111,927.
However, an idea of circulating ink in the ink-jet apparatus is not disclosed in the above Unexamined Japanese Patent Publication No. 2001-121693 and Unexamined Japanese Patent Publication No. 60-217160 at all. That is, the ink-jet apparatuses disclosed in Unexamined Japanese Patent Publication No. 2001-121693 and Unexamined Japanese Patent Publication No. 60-217160 are simply based on a technique to eject liquid held in the pressure chamber (ink supply path) from a nozzle hole by driving the piezoelectric element, and they are not based on a technique to provide an ink supply flow path and an ink discharge flow path and circulate ink therebetween.
Especially, in the configuration of the ink-jet apparatus in Unexamined Japanese Patent Publication No. 2001-121693, the ink could stagnate in a corner part of the pressure chamber or the nozzle hole, and the nozzle hole could be clogged. Thus, in a case where the ink has high viscosity, it is hard to eject the ink from the nozzle hole. In addition, as for the ink-jet head in Unexamined Japanese Patent Publication No. 60-217160, a pressure generated by driving electrostrictive element 4 and applied to the ink flowing in ink supply path 11 is dispersed to the upstream side of electrostrictive element 4 (in a direction opposite to nozzle 9), so that it is difficult to eject the ink strongly toward nozzle 9.


Methods, systems, and devices for wireless communication are described. A user equipment (UE) may receive multiple uplink grants that schedule uplink transmissions for two different radio access technologies (RATs) during overlapping time resources. The UE may adjust the power for one of the uplink transmissions based on the temporal proximity of the second received uplink grant relative to the first uplink transmission. The UE may adjust the power of the uplink transmission by partially or completely reducing its power.

The following relates generally to wireless communications, and more specifically to dual connectivity transmission techniques.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), or discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-s-OFDM). A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
In some cases, a UE may be a multi radio access technology (RAT) dual connectivity (MR-DC) UE that supports simultaneous connections to two base stations using different RATs. For example, a UE may be connected to an LTE base station at the same time that it is connected to an NR base station. In such cases, uplink grants from the LTE base station and the NR base station may occasionally schedule uplink resources that collide (e.g., the UE may be assigned overlapping uplink resources in the time domain). The UE receiving these grants, however, may not be capable of transmitting both scheduled uplink transmissions (e.g., the UE may not have the power or processing resources to properly transmit both uplink transmissions).

Dual connectivity transmission techniques


Apparatus and methods for combustion of fuel includes, in some embodiments, a fuel nozzle which injects fuel into a combustion channel of a wave rotor combustor or a pulse detonation combustor. In some embodiments the combustion process includes a backward-propagating detonation wave within a substantially closed channel which compresses discrete quantities of combustible and noncombustible mixture. Yet other embodiments include a precombustion chamber integrated into the wave rotor, the outlet stator or both.

The ability to produce pressure gain by a confined, intermittent combustion process (ideally constant-volume combustion) is a significant principle for improving gas turbine efficiencies. Indeed, the earliest working gas turbine around 1908, known as the Holzwarth engine, had valved and pulsating combustion chambers operated on a controlled explosive combustion process. However, ineffective utilization of wave action in the combustion chamber resulted in the non-uniform outflow and poor overall thermal efficiency. Holzwarth's design was surpassed by gas turbines that employed nearly constant-pressure heat addition, and newly developed compressor technology. Later, German scientists exploited pulsed combustion and wave action in the pulse-jet engine that powered the V-1 Buzz Bomb in World War II. Thereafter, theoretical and experimental efforts on various designs of pulse combustors for gas turbines have yielded limited gains, and integration with steady-flow machinery has been challenging. Recent efforts to develop pulse detonation engines (PDE) for propulsion applications has raised interest in all pressure-gain concepts, but the integration issue remains difficult for gas turbines.
Conventional steady-flow combustors are inherently subject to a pressure loss with addition of thermal energy, although ideally constant pressure. Cyclic constant-volume combustion can provide pressure gain, which boosts engine performance by effecting a more efficient thermodynamic cycle known as the Humphrey cycle. This is illustrated in FIG. 1, comparing schematic temperature-entropy (T-s) diagrams of a conventional Brayton engine (1-2-3b-4b) and the replacement Humphrey cycle (1-2-3-4) for fixed turbine inlet temperature and compressor discharge pressure. Pressure loss in conventional combustors (P3b<P2) is substituted with pressure to gain combustion process (P3>P2), enabling greater turbine power output and higher cycle efficiency for the same combustion energy input.
Comparison of ideal entropy generation during combustion for the two cycles is revealing. Air-cycle calculation with constant specific heat ratio of 1.333 shows the ratio of entropy production for the Brayton and Humphrey cycles is 0.75, the inverse of the specific heat ratio. This 25% ideal reduction in entropy production represents substantial potential over years of effort to improve the efficiency of turbomachinery components, making the pressure-gain combustion concept a revolutionary improvement for modern gas turbines. Constant-volume combustion can be achieved by both deflagrative and detonative combustion modes. While deflagrative combustion in a closed system at roughly constant volume is commonly achieved in piston engines, the use of detonative combustion in an intermittently open-system to achieve constant volume combustion has recently received significant attention. Specifically, pulse detonation engines (PDE) have been designed to create simple direct-thrust propulsion systems. In a PDE, detonable mixtures of fuel and air are admitted into open-end tube(s) and ignited, generating a detonation that provides a pulse of pressure and thrust. Following early work on single-tube PDE, recent work has focused on multiple tube PDE designs that provide more continuous but still unsteady output. Among various possible configurations is the rotary-valved multiple-tube PDE proposed by Bussing. In this design, several stationary detonation chambers are arranged circularly and coupled to an air/fuel duct via a common rotary valve. Such arrangements allow some of the PDE chambers to be filled while detonation occurs in other PDE chambers.
Various embodiments of the inventions described herein provide novel and nonobvious improvements of the incorporation of pulsed combustions and wave action combustion into steady-flow machinery.

Direct injection of a discrete quantity of fuel into channels of a wave rotor engine

Indiana University Research and Technology Corp.


It is an object of the invention to provide a semiconductor wafer obtained by forming a semiconductor thin film with uniform resistivity on a main surface of a semiconductor single crystal substrate of 300 mm or more in diameter.

This invention relates to a semiconductor wafer and a production method therefor and particularly, a semiconductor wafer obtained by forming a semiconductor thin film having a uniform resistivity distribution on a main surface of a large diameter semiconductor substrate and a production method therefor.
In company with recent miniaturization of an electronic device, not only has the use of semiconductor wafers each obtained by forming a silicon single crystal thin film on a main surface of a silicon single crystal substrate increased, but a more uniform resistivity distribution of the silicon single crystal thin film has also been required. The term uniform resistivity distributions used here, to be detailed, means that a resistivity distribution across the surface of the silicon single crystal thin film is uniform. Further, a larger diameter has also been demanded on a semiconductor wafer together with the uniform resistivity distribution. A horizontal, single wafer vapor phase growth apparatus has been mainly employed as an apparatus for growing a silicon single crystal thin film on a main surface of a silicon single crystal substrate keeping pace with use of a large diameter semiconductor wafer.
Description will be below given of a horizontal, single wafer vapor phase growth apparatus generally employed with reference to FIGS. 5 and 6, wherein FIG. 5 is a sectional view in a horizontal plane showing a conventional horizontal, single wafer vapor phase growth apparatus in a simplified manner and FIG. 6 is a vertical sectional view showing the apparatus in a simplified manner. As shown in FIGS. 5 and 6, in a conventional horizontal, single wafer vapor phase growth apparatus, a susceptor 14 on which a silicon single crystal substrate 12 is horizontally placed is disposed at the bottom of the middle portion of a transparent quartz glass reaction chamber 10 installed along a horizontal direction and the susceptor 14 is coupled with a rotation unit (not shown) through a rotary shaft 16.
Further, a gas inlet port 18 is provided atone end in a length direction of the reaction chamber 10 and a gas outlet port 20 is provided at the other end thereof. With this construction, a flow of a gas which is introduced through the gas inlet port 18 into the reaction chamber 10 and discharged through the gas outlet port 20 to the outside passes over a main surface of the silicon single crystal substrate 12 placed on the susceptor 14 almost along a length direction of the reaction chamber 10. Further, the gas inlet port 18 of the reaction chamber 10 is constructed of six inlet ports 18a to 18f spread in a width direction of the reaction chamber 10. Among the six inlet ports 18a to 18f, a pair of two inlet ports at the innermost side (hereinafter simply referred to as inner inlet ports) 18a and 18b are arranged in symmetry with respect to an imaginary central axis along a length direction of the reaction chamber 10, passing through the center of the main surface of the silicon single crystal substrate 12 on the susceptor 14, and this arrangement of the inner inlet ports 18a and 18b applies to not only a pair of two inlet ports at the outermost side (hereinafter simply referred to as outer inlet ports) 18e and 18f, but also a pair of two inlet ports each between one of the two inner inlet ports and the corresponding one of the two outer inlet ports (hereinafter simply referred to as middle inlet ports) in the same way.
To be more detailed, the inner inlet ports 18a and 18b are directed toward points in the vicinity of the center of the main surface of the silicon single crystal substrate 12 on an imaginary central axis along a width direction of the reaction chamber 10, passing through the center of the main surface of the silicon single crystal substrate 12 on the susceptor 14, and the outer inlet ports 18e and 18f are directed toward points in the vicinity of the outer periphery of the main surface of the silicon single crystal substrate 12 on the imaginary central axis line and the middle inlet ports 18c and 18d are directed toward points between the central portion and the outer peripheral portion of the main surface of the silicon single crystal substrate 12 on the imaginary central axis line.
Further, the six inlet ports 18a to 18f are all connected to a common gas pipe 22. The common gas pipe 22 are branched in three ways and the branches are connected to a gas source (not shown) of hydrogen (H2) gas as a carrier gas, a gas source (not shown) of a semiconductor raw material gas and a gas source (not shown) of a dopant gas through mass flow controllers MFC 24, 26 and 28, respectively, as gas flow rate regulators.
Further, outside of the reaction chamber 10, an infrared radiation lamp 30, for example, as a heat source heating the silicon single crystal substrate 12 placed on the susceptor 14 is disposed and by supplying a power to the infrared radiation lamp 30, the main surface of the silicon single crystal substrate 12 is heated to a predetermined temperature. In addition, cooling means (not shown) for cooling the infrared radiation lamp 30 and an outer wall of the reaction chamber 10 is equipped.
Then, description will be made of a method for forming a silicon single crystal thin film on the main surface of the silicon single crystal substrate 12 using the conventional horizontal, single wafer vapor growth apparatus shown in FIGS. 5 and 6.
First, the silicon single crystal substrate 12 is horizontally placed on the susceptor 14 of the reaction chamber 10. Following this, H2 gas is supplied into the reaction chamber 10 from the gas source of H2 gas through MFC 24, the common gas pipe 22 and through the six inlet ports 18a to 18f to replace the atmosphere in the reaction chamber 10 with hydrogen. Further, with the rotation device, the susceptor 14 is rotated through the rotary shaft 16 clockwise as shown by arrow marks of FIGS. 5 and 6 while the silicon single crystal substrate 12 is horizontally placed on the susceptor 14. Then, with the infrared radiation lamp 30, the silicon single crystal substrate 12 on the susceptor 14 is heated to raise a temperature of the main surface thereof to a predetermined one.
After doing so, the semiconductor raw material gas and the dopant gas are supplied into the reaction chamber 10 from the respective gas sources of the semiconductor raw material gas and the dopant gas through MFC 26 and 28, the common gas pipe 22 and the six inlet ports 18a to 18f.
At this time, not only are flow rates of H2 gas as a carrier gas, the semiconductor raw material gas and the dopant gas controlled individually and precisely by MFC 24, 26 and 28, respectively, but the gases are mixed after the individual control and introduced into the reaction chamber 10 as a process gas having the raw material gas and the dopant gas of respective constant concentrations with almost no diffusion in a width direction through the six inlet ports 18a to 18f disposed in a width direction of the reaction chamber 10.
The process gas introduced into the reaction chamber 10 passes over the main surface of the silicon single crystal substrate 12 placed horizontally on the susceptor 14 rotating about the rotary shaft 16 as a center in one direction and in almost parallel to the main surface. During the passage over the main surface, a chemical reaction arises to grow the silicon single crystal thin film 32 in vapor phase on the main surface of the silicon single crystal substrate 12.
In a case where a silicon single crystal thin film 32 was formed on the main surface of the silicon single crystal substrate 12 using the conventional horizontal, single wafer vapor phase growth apparatus shown in FIGS. 5 and 6 as described above, and when the diameter of a silicon single crystal substrate 12 was 200 mm or less, a resistivity distribution along a diameter of the silicon single crystal thin film 32 formed on the main surface of the silicon single crystal substrate 12 was almost uniform. However, when a diameter of the silicon single crystal substrate 12 was larger than 200 mm, for example the diameter of as large as 300 mm, a conspicuous non-uniformity occurred in a resistivity distribution along a diameter direction of the silicon single crystal thin film 32. That is, a resistivity in the vicinity of the outer periphery of the silicon single crystal thin film 32 of a diameter of 300 mm was sharply reduced compared with the central portion other than an area in the vicinity of the outer periphery.
The sharp reduction in resistivity in the vicinity of the outer periphery of the silicon single crystal thin film 32 is estimated to be caused by the so-called auto-doping phenomenon. Here, the auto-doping phenomenon will be explained below:
When the silicon single crystal thin film 32 is grown in vapor phase on the main surface of the silicon single crystal substrate 12, an impurity added originally in the silicon single crystal substrate 12 is released into the reaction atmosphere through etching by H2 gas in the reaction atmosphere, occurring on a rear main surface of the silicon single crystal substrate 12 heated at a high temperature and works as a dopant gas. The dopant gas generated from the rear main surface of the silicon single crystal substrate 12 is migrated along the side surface of the silicon single crystal substrate, further comes onto the front main surface to be incorporated into the silicon single crystal thin film 32 during vapor phase growth. In such a way, since the dopant gas produced on the rear main surface of the silicon single crystal substrate 12 is supplied into the silicon single crystal thin film 32 in addition to a dopant gas introduced intentionally from a gas inlet port 18, an impurity more than necessary is added and thereby a resistivity of the silicon single crystal thin film 32 is forcibly reduced lower than a target value. Since a concentration of the dopant gas, around the silicon single crystal substrate, produced on the rear main surface, migrated along the side surface and coming onto the front main surface is highest at the outer peripheral portion and reduced toward the central portion, a sharp reduction in resistivity occurs in the vicinity of the outer periphery of the silicon single crystal thin film 32.
Such an auto doping phenomenon occurs theoretically independent of a size of the silicon single crystal substrate 12. Actually, however, in a conventional case where a diameter of a silicon single crystal substrate 12 was less than 200 mm, reduction in resistivity in the vicinity of the outer periphery of a silicon single crystal thin film 32, caused by the auto-doping phenomenon was not conspicuous, so that a resistivity distribution across the silicon single crystal thin film 32 fell within an allowable range.
When this inventor used a silicon single crystal substrate 12 of 300 mm in diameter and a low resistivity to carry out vapor phase growth on a main surface thereof in order to respond to a recent demand for a semiconductor wafer of a large diameter, the inventor experienced a sharp reduction in resistivity in the vicinity of the outer periphery of the silicon single crystal thin film 32 due to the auto-doping phenomenon, with the result that a problem became obvious since there arose a conspicuous non-uniformity in a resistivity distribution along a diameter thereof.
It should be noted that it has been known, as means suppressing occurrence of the auto-doping phenomenon, that a film made of silicon nitride or silicon oxide is formed on a rear main surface of the silicon single crystal substrate 12. In this method, however, there is a fear that a film for prevention of an auto-doping phenomenon formed on the rear main surface of the silicon single crystal substrate 12 becomes a particle generation source and/or a metal contamination source, which entails a problem of a quality of the silicon single crystal thin film 32 formed on the front main surface of the silicon single crystal substrate 12 being degraded. In this method, in addition to an extra step of forming an auto-doping preventive film on the rear main surface of the silicon single crystal substrate 12, another extra step of removing the auto-doping preventive film after forming the auto-doping preventive film becomes necessary, which produces a problem of reduction in productivity and increase in production cost combined.
The invention has been made in light of the above described problems and it is accordingly an object of the invention to provide not only a semiconductor wafer obtained by forming a semiconductor thin film having a uniform resistivity distribution on a main surface of a large diameter silicon single crystal substrate of 300 mm or more in diameter, but a production method for a semiconductor wafer by which a semiconductor thin film having a uniform resistivity distribution is formed on a front main surface of a large diameter semiconductor single crystal substrate of 300 mm or more in diameter without forming an auto-doping preventive film on the rear main surface thereof. The above described task is achieved by a semiconductor wafer and a production method therefor relating to the invention described below:
That is, a semiconductor wafer relating to the invention is characterized by that the semiconductor wafer has a construction in which a semiconductor thin film of 8% or less in resistivity distribution along a diameter is formed on a p-type semiconductor single crystal substrate of a diameter ranging from 300 mm to 400 mm, both limits being included, and a resistivity ranging from 0.01 xcexa9xc2x7cm to 0.02 xcexa9xc2x7cm, both limits being included. Here, a value representing a resistivity distribution along a diameter of a semiconductor thin film, that is, 8% or less is calculated by the following formula:
(Maximum resistivityxe2x88x92Minimum resistivity)/average resistivity over all measurement pointsxe2x80x83xe2x80x83(1)
In such a manner, in a semiconductor wafer relating to the invention, a semiconductor thin film of 8% or less in resistivity distribution along a diameter is formed on a main surface even of a p-type semiconductor single crystal substrate as large as from 300 mm to 400 mm, both limits being included, in diameter and as low as from 0.01 xcexa9xc2x7cm to 0.02 xcexa9xc2x7cm, both limits being included, in resistivity, and thereby a large diameter and a uniform resistivity distribution as characteristics of a recent semiconductor wafer are both achieved, which contributes largely to increase in throughput and yield of semiconductor chips in production.
It is preferable that in a semiconductor wafer relating to the invention, a resistivity distribution along a diameter of a semiconductor thin film formed on a main surface of a p-type semiconductor single crystal substrate is within xc2x14% or less. Here, a value representing a resistivity distribution along a diameter of a semiconductor thin film, that is, xc2x14% or less is calculated by the following formula:
(Maximum resistivityxe2x88x92Minimum resistivity)/(Maximum resistivity+Minimum resistivity)xe2x80x83xe2x80x83(2)
In this case, uniformity in resistivity distribution required for a recent semiconductor wafer is achieved with a high accuracy, thus further contributing to increase in yield of semiconductor chips in production.
Further, in a semiconductor wafer relating to the invention, a diameter of the semiconductor single crystal substrate is preferably 300 mm. At the present stage, since a semiconductor single crystal substrate with a diameter up to 300 mm can be produced in a stable manner with high quality, it is practically enjoyed to an full extent that a resistivity distribution of a semiconductor thin film along a diameter is achieved with uniformity of 8% or less (in a case of calculation with the above described formula (1)) or within xc2x14% or less (in a case of calculation with the above described formula (2)) on a main surface of a semiconductor single crystal substrate as low as from 0.01 xcexa9xc2x7cm to 0.02 xcexa9xc2x7cm, both limits being included, in resistivity.
Further, it is preferable that a semiconductor single crystal substrate is a silicon single crystal substrate and a semiconductor thin film is a silicon single crystal thin film. That is, since a large diameter and a uniform resistivity distribution as characteristics of a silicon single crystal wafer,which is a main stream of currently used semiconductor wafers, are both achieved, there arises expectation of a wide application of the silicon single crystal wafer in various aspects in fabrication of semiconductor devices.
Further, in a production method for a semiconductor wafer relating to the invention, a semiconductor raw material gas is supplied through a plurality of gas inlet ports disposed in a width direction of the reaction chamber onto a main surface of a semiconductor single crystal substrate rotating in a reaction chamber in one direction in almost parallel to the main surface thereof to grow a semiconductor thin film on the main surface thereof in vapor phase and a dopant gas is supplied from gas inlet ports in the inner side among the plurality of gas inlet ports.
In such a manner, in a production method of a semiconductor wafer relating to the invention, a semiconductor raw material gas is supplied through the plurality of gas inlet ports disposed in a width direction of the reaction chamber onto a main surface of a semiconductor single crystal substrate in one direction in almost parallel to the main surface thereof and a dopant gas is supplied from gas inlet ports in the inner side among the plurality of gas inlet ports, that is, without supplying the dopant gas from gas inlet ports in the outer side among the plurality of gas inlet ports, with the result that a concentration of the dopant gas supplied into the vicinity of the outer periphery of the main surface of a semiconductor single crystal substrate is lower than that supplied into the central portion other than an area in the vicinity of the outer periphery on a relative basis. In this situation, however, a dopant gas produced on a rear main surface of the semiconductor single crystal substrate, migrating along the side surface thereof and coming onto the front main surface thereof is supplied in the vicinity of the outer periphery thereof by the auto-doping phenomenon. For this reason, a dopant gas supplied from the gas inlet ports and a dopant gas supplied by the auto-doping phenomenon are combined and thereby, a concentration of the combined dopant gas supplied onto the front main surface of the semiconductor single crystal substrate can be almost uniform across the whole of the front main surface. As a result, a resistivity distribution along a diameter of the semiconductor thin film grown in vapor phase on the front main surface of the semiconductor single crystal substrate can be more uniform.
Further, in a production method for a semiconductor wafer relating to the invention, the plurality of gas inlet ports are preferably composed of three kinds: an inner inlet port disposed at the innermost side in a width direction of a reaction chamber, an outer inlet port disposed at the outermost side in the width direction thereof and a middle inlet ports disposed between the inner inlet port and the outer inlet port and gas inlet ports disposed In the inner side among the plurality of gas inlet ports include the inner inlet port and the middle inlet port.
In such a manner, in a production method for a semiconductor wafer relating to the invention, the plurality of gas inlet ports include the three kinds of the inner gas inlet port, the outer gas inlet port and the middle gas inlet port and, on an imaginary central axis along a width direction of the reaction chamber, passing through the center of the main surface of the semiconductor single crystal substrate, a semiconductor raw material gas is supplied onto an area in the vicinity of the center of the main surface of the semiconductor single crystal substrate from the inner gas inlet port, onto an area in the vicinity of the outer periphery thereof from the outer gas inlet port and onto an intermediate area between the area in the vicinity of the center and the area in the vicinity of the outer periphery from the middle gas inlet port, while a dopant gas is not supplied from the outer gas inlet port but from the inner and middle gas inlet ports. In this situation, since while a concentration of a dopant gas supplied in the vicinity of the outer periphery of the main surface of the semiconductor single crystal substrate is lower than those of the dopant gas supplied to the area in the vicinity of the central portion and the intermediate area on a relative basis, an additional dopant gas produced by the auto-doping phenomenon is supplied to the area in the vicinity of the outer periphery, therefore a concentration of the combined dopant gas supplied to across all the main surface of the semiconductor substrate is almost uniform. Accordingly, a resistivity distribution along a diameter of the semiconductor thin film grown in vapor phase on the main surface of the semiconductor single crystal substrate becomes more uniform with no need to provide an extra step of forming an auto-doping protective film on the rear main surface thereof.
It should be noted that while description is made of the case where among the plurality of gas inlet ports disposed in a width direction of a reaction chamber, two kinds of inner and middle gas inlet ports are provided as gas inlet ports disposed in the inner side of the plurality of gas inlet ports for supply of a dopant gas, three or more kinds of gas inlet ports can also be provided as the gas inlet ports disposed in the inner side thereof for supply of a dopant gas according to a size of a semiconductor single crystal substrate.
Further, in a production method for a semiconductor wafer relating to the invention, it is further preferable that dopant gas rates supplied from the inner and middle inlet ports are individually controlled.
In such a manner, since in a production method for a semiconductor wafer, dopant gas rates supplied onto the area in the vicinity of the center and the intermediate area of a main surface of a semiconductor single crystal substrate other than the area in the vicinity of the outer periphery thereof are individually controlled on an imaginary central axis along a width direction of the reaction chamber, passing through the center of the main surface of the semiconductor single crystal substrate, therefore concentrations of a dopant gas supplied onto the area in the vicinity of the center and the intermediate area can be closer in magnitude to each other, resulting in more uniform resistivity distribution along a diameter of a semiconductor thin film grown in vapor phase on the main surface of a semiconductor single crystal substrate.
It should be noted that in a production method for a semiconductor wafer relating to the invention, it is preferable that as a semiconductor single crystal substrate, there is used a p-type semiconductor single crystal substrate of a diameter ranging from 300 mm to 400 mm, both limits being included, and especially a diameter of 300 mm and of a resistivity ranging from 0.01 xcexa9xc2x7cm to 0.02 xcexa9xc2x7cm, both limits being included.
That is, since in a case where a semiconductor single crystal substrate is of a diameter in the range of from 300 mm to 400 mm, both limits being included, and among them, especially, a diameter of 300 mm, a semiconductor single crystal substrate of which can be produced in a stable manner with high quality at the present stage, reduction in resistivity in the vicinity of the outer periphery of a semiconductor single crystal thin film caused by the auto-doping phenomenon becomes conspicuous, therefore stoppage of dopant gas supply onto an area in the vicinity of the outer periphery from a gas inlet port exerts practically a sufficient influence to make a resistivity distribution along a diameter of the semiconductor thin film uniform.
It should be noted that in a production method for a semiconductor wafer relating to the invention, a diameter of a semiconductor single crystal substrate is not limited to the range of from 300 mm to 400 mm, both limits being included, but a diameter beyond 400 mm thereof can be still used in the production method. In this case, as described above, a measure is conceived in which three or more kinds of gas Inlet ports are provided as gas inlet ports in the inner side for supply of a dopant gas.
Further, in a case where a semiconductor single crystal substrate of a low resistivity lower than 0.01 xcexa9xc2x7cm is used, since an influence of the auto-doping phenomenon increases and reduction in resistivity in the vicinity of the outer periphery of a semiconductor single crystal thin film caused by an increased influence is too sharp, simple stoppage of supply of a dopant gas onto area in the vicinity of the outer periphery of the semiconductor single crystal thin film from a gas inlet port is hard to exert a sufficient effect to make a resistivity distribution along a diameter of the semiconductor single crystal thin film uniform. On the other hand, in a case where a high resistivity semiconductor single crystal substrate of a resistivity higher than 0.02 xcexa9xc2x7cm is used, since an influence of the auto-doping phenomenon decreases and reduction in resistivity in the vicinity of the outer periphery of a semiconductor single crystal thin film caused by the influence thereof becomes small, there arises no need for stoppage of supply of a dopant gas on to the area in the vicinity of the outer periphery from a gas inlet port, but depending on circumstances, stoppage of supply of a dopant gas onto the area in the vicinity of the outer periphery, to the contrary, has a risk to induce non-uniformity in resistivity distribution across all the semiconductor single crystal thin film. Therefore, in a case of a resistivity of a semiconductor single crystal substrate ranging from 0.1 xcexa9xc2x7cm to 0.02 xcexa9xc2x7cm, both limits being included, stoppage of supply of a dopant gas onto an area in the vicinity of the outer periphery of the substrate from a gas inlet port works most effectively to make a resistivity distribution along a diameter of a semiconductor thin film uniform.
Further, in a production method for a semiconductor wafer relating to the invention, it is preferable that a semiconductor single crystal substrate is a silicon single crystal substrate and a semiconductor thin film is a silicon single crystal thin film. That is, a large diameter and a uniform resistivity distribution of a silicon single crystal wafer that is currently a main stream of semiconductor wafers are both achieved and thereby, a wide application of the silicon single crystal wafer in various aspects are expected in fabrication of semiconductor devices.

Semiconductor wafer and production method therefor

Abstract: When a process gas is supplied to over a main surface of a silicon single crystal substrate 12 in rotation in almost parallel to the main surface thereof in one direction in a reaction chamber 10 through six inlet ports 18a to 18f disposed in width direction of the reaction chamber 10, H2 gas, a semiconductor raw material gas and a dopant gas are supplied onto an area in the vicinity of the center of the main surface of the silicon single crystal substrate 12 and an intermediate area thereof through the inner inlet ports 18a and 18b and the middle inlet ports 18c and 18d, and only H2 gas and the semiconductor raw material gas without the dopant gas are supplied onto an area in the vicinity of the outer periphery thereof from the outer inlet ports 18e and 18f. In such arrangement, a dopant gas produced by the auto-doping phenomenon is supplied onto the area in the vicinity of the outer periphery of the main surface of the silicon single crystal substrate 12. For this reason, the dopant gases from both sources are combined, thereby a concentration of the dopant gas supplied over all the main surface of the silicon single crystal substrate 12 is almost uniform.


A polyurethane resin-bonded pigment may exhibit excellent image density, dispersibility, storage stability, and resolubility, and may form an ink film that exhibits marker resistance and rubfastness. The polyurethane resin-bonded pigment is produced by bringing (I) a pigment having a surface acidic group into contact with (II) a basic compound having two or more amino groups selected from a primary amino group and a secondary amino group in its molecule in an aqueous medium to obtain a pigment having an unreacted surface amino group, and bringing the pigment having an unreacted surface amino group into contact with (III) a water-dispersible polyurethane resin having an isocyanate end group and (IV) a polyisocyanate compound to bond the pigment having an unreacted surface amino group and the water-dispersible polyurethane resin (III) having an isocyanate end group via a urea bond.

In recent years, an aqueous ink that is safe and has small environmental impact has been widely used in various fields instead of an organic solvent-based ink. In business applications or the like, an odorless aqueous coloring material is indispensable as an ink used for printing in offices. In industrial applications, there has been an increasing tendency to reduce the use of an organic solvent as much as possible from the viewpoint of an improvement in working environment, an improvement in safety of ink and paint, and waste disposal. An aqueous coloring material also has an advantage in that the production cost can be reduced as compared with an organic solvent-based coloring material since special equipment (e.g., explosion-proof system, ventilator, and organic solvent recovery unit) is unnecessary during production.
A dye or a pigment has been mainly used as the aqueous coloring material depending on the application. A dye can easily form a high-resolution image that exhibits an excellent tone, but exhibits poor light resistance as compared with a pigment. A pigment exhibits poor dispersibility as compared with a dye, but exhibits excellent water resistance and light resistance. A number of pigment inks have been developed along with the development of a dispersion technique.
An aqueous liquid ink for gravure printing or offset printing has been developed. An inkjet recording method has been most widely used as an aqueous ink recording method for office applications.
The inkjet recording method discharges ink droplets from a minute nozzle head to record characters or figures on the surface of a recording medium (e.g., paper). The noncontact inkjet recording method can implement easy on-demand full-color printing of an image on various recording media (e.g., plain paper) without requiring a printing plate.
An inkjet printer that utilizes the inkjet recording method discharges ink droplets from a minute nozzle head to record characters or figures on the surface of a recording medium (e.g., paper). Typical inkjet printing methods include a Bubble Jet (registered trademark) method and a piezo method. The Bubble Jet method instantaneously heats an ink introduced into the nozzle head using a heater to produce bubbles, and intermittently discharges the ink by utilizing the volume expansion due to the bubbles. The piezo method converts an electrical signal into a mechanical signal using an electrostrictive element (piezoelectric element), and intermittently discharges ink droplets stored in the nozzle head.
A black inkjet printer ink composition (inkjet ink composition) has been widely used in offices and the like mainly in order to print documents. A number of aqueous black pigment ink compositions that are optimized for the recording method and the recording speed of each printer have been proposed.
For example, Patent Document 1 discloses an aqueous black pigment ink composition that is provided with improved dispersibility in an aqueous medium by hydrophilizing the surface of the black pigment. However, since the ink composition disclosed in Patent Document 1 may penetrate when printed on plain paper, a decrease in image density, offset, curling of the recording paper, and the like may occur. In particular, since the amount of ink discharged per unit time has increased along with an increase in printing speed of inkjet printers, a sufficient image density may not be obtained when using a related-art aqueous black pigment.
Since a pigment exhibits a strong interparticle cohesive force, but exhibits weak affinity to an organic polymer, water, an organic solvent, and the like, it is very difficult to uniformly mix or disperse a pigment under normal mixing or dispersion conditions. In order to deal with this problem, attempts have been made to improve the dispersibility of a pigment by improving the affinity of the pigment to a solid or liquid component by causing a dispersant (e.g., surfactant or resin) to be adsorbed on the surface of the pigment, or coating the entire surface of the pigment with the dispersant (see Patent Document 2, for example).
Since a printer used for industrial applications has a high print speed, and cannot be frequently subjected to head cleaning as compared with a printer used for personal applications, an inkjet ink composition that does not contaminate or clog the head during continuous or intermittent inkjet operations, and exhibits resolubility (i.e., the dried ink composition is redissolved in the undried ink composition, and does not contaminate or clog the nozzle head during continuous or intermittent inkjet operations) has been desired. The same technical problem exists in the field of spray coating compositions and the like.

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