A method of depositing material on a substrate comprises providing a reactor with a reaction chamber having a first volume, and contacting a surface of a substrate in the reaction chamber with a first precursor at the first chamber volume to react with and deposit a first layer on the substrate. The method further includes enlarging the reaction chamber to a second, larger volume and removing undeposited first precursor and any excess reaction product to end reaction of the first precursor with the substrate.

1. Field of the Invention
The present invention relates to reactors used in the semiconductor manufacturing industry and, in particular, to a reactor for pulsed layer deposition of thin films in the fabrication of integrated circuits.
2. Description of Related Art
A primary goal of the semiconductor manufacturing industry is to reduce the size of integrated circuits in order to them to perform more operations in a shorter time. As integrated circuit device features become smaller, several technical difficulties are presented. One such problem is depositing conformal thin films in holes or trenches having a small diameter or a small width-to-depth ratio. One standard technique for depositing such thin films has been chemical vapor deposition (CVD), which works well for feature sizes on the order of 120 nm and smaller. However, CVD may not be extendable to high aspect ratio features at these dimensions. Pulsed layer deposition (PLD) has been seen as a likely replacement for film deposition and holes below 120 nm in width and for the high aspect ratio features.
PLD is useful for depositing thin films having two components. The process generally consists of four steps, which may be repeated to produce films of desired thickness. The steps are normally conducted in a reactor with a controlled environment. The first step consists of saturating a surface with the first precursor or reactant needed to create the film, followed by removing the excess byproducts of the first reaction and any unreacted precursor from the reactor. The next step consists of saturating the surface with a second precursor or reactant in order to form the desired film. The last step is to remove unwanted excess byproducts from the third step and any unreacted precursor.
The precursor exposure steps of PLD are said to be self-limiting, that is, the amount of material deposited on the surface stops depositing after a relatively short period of time. However, in order for the deposition reactions of steps one and three to go to completion, the surface must receive a high exposure of the precursor. This is achieved if the precursor is allowed to remain for a long period above the surface or if the concentration of the precursor above the wafer is high. Provided the precursor exposures are high and the purging performed during the second and third steps are sufficient, there results a thin film consisting of the reaction product of the two components. The purging steps are sufficient if concentrations of the un-reacted precursors and reaction byproducts are low enough to minimize or eliminate one precursor or its byproducts from contacting, and possibly reacting with, the second precursor or its byproducts.
In addition to the steps outlined above, there are additional practical requirements. First, each step should be as short as possible to fulfill the requirement that the thin film be formed as fast as possible to make the entire process commercially viable for ultra large scale integration (ULSI) of the circuits. Second, the smallest possible amount of precursor should be used because precursor costs must be minimized to make the process commercially viable, and un-reacted precursor and byproducts must be minimized to reduce the need for abatement of environmentally harmful substances. Accordingly, the requirements for a rapid process and use of minimum amount of precursor, coupled with the requirements of high exposure and sufficient purging, necessitate trade offs to be made in the PLD process.

Method and apparatus for modulation of precursor exposure during a pulsed deposition process


Antisense oligonucleotides which hybridize with nuclear factor-xcexaB(NF-xcexaB) mRNA and methods of using these oligonucleotides.

1. Field of the Invention
This invention relates generally to methods and compositions useful in inhibiting disorders dependent upon expression of the inducible transcription factor NF-xcexaB.
2. Description of Related Art
The NF-xcexaB transcription activator is a multiprotein complex which can rapidly induce the synthesis of defense and signalling proteins upon exposure of cells to a wide variety of mostly pathogenic agents. Three protein subunits, IxcexaB, p50, and p65, control the biological functions of NF-xcexaB. IxcexaB is a 35-43 kDa subunit which inhibits the DNA-binding of NF-xcexaB and serves to retain NF-xcexaB in an inducible form in the cytoplasm of unstimulated cells. Upon stimulation of cells, IxcexaB dissociates from the inactive complex with p65 and p50. The released p50-p65 complex can then migrate into the nucleus and potently transactivate genes. p50, one of the two DNA-binding subunits of NF-xcexaB, serves to recognize the more highly conserved half site in decameric sequence motifs with the consensus sequence GGGRNNYYCC. p50 has homologies to the rel and dorsal proteins, both of which are also involved in cytoplasmic/nuclear signalling, and is identical to factors known as KBF1, H2TF1 and EBP-1. p50 is synthesized as an inactive precursor of 110 kDA.
The other DNA binding subunit, p65, binds to the less conserved half site of kB motifs and is apparently also homologous to rel/dorsal proteins. The combination of p50 and p65 DNA binding subunits in NF-xcexaB extends the repertoire of binding motifs recognized with high affinity. Only p65 appears to bind IxcexaB. The inducibility of NF-xcexaB is thus equally dependent on the presence of p65 as of IxcexaB. The NF-xcexaB system is so far unique among transcription factors in that the interaction of three distinct subunits control multiple regulatory characteristics of a transcription activator including the subcellular localization and the activity, inducibility, and specificity of DNA binding.
Many different binding sites for NF-xcexaB have been characterized and for most the base requirements for protein binding have been defined by methylation interference analysis or other footprinting techniques (Baeuerle, Biochem Biophys. Act., 1072:63, 1991). Most binding sites are decameric, but some are undeca- or dodecameric. The latter may arise from NF-xcexaB binding in a mutually exclusive manner to two or three decameric motifs within the longer sequences. An alternative explanation is that p50-p65 or the p50 dimer can contact 10, 11 or even 12 base pairs. Support for the latter hypothesis comes from mutational analysis of the enhancer of the MHC class I gene H-2Kb.
Among those disorders which are linked to activation of NF-xcexaB is leukemia caused by the retrovirus HTLV-1. Human T-cell leukemia virus (HTLV-1) is recognized as the etiologic agent of the human malignancy, adult T cell leukemia (B. J. Poiesz, Proc. Natl. Acad. Sci. USA, 77:7415, 1980; D. J. Slamon, et al., Science, 226:61, 1984; W. C. Goh, et al., ibid. 297:1227, 1985).
Circumstantial data has implicated the HTLV-I encoded tax gene in leukemo-genesis. This gene encodes a 40kD protein that causes transcriptional transactivation of viral gene expression and also activates expression of certain cellular genes that are important for growth (A. J. Cann, et al., Nature 318:571, 1985; B. K. Felber, et al., Science, 229:675, 1985; J. Fujisawa, et al., Embo Journal 5:713, 1986). In vitro studies have demonstrated that tax can activate the promoters of the interleukin 2 receptor (IL-2R) a-chain, GM-CSF, fos, PDGF, IL-6, NGF, TGF-xcex2, HIV LTR as well as its own LTR (D. J. Slamon et al., Science, 226:61, 1984; W. C. Goh et al., ibid., 227:1227, 1985; J. Inoue, et al., Embo Journal 5:2883, 1986; S. Miyatake, et al., Mol. Cell. Biol. 8:5581, 1988; K. Nagata, et al., J. Virol. 63:3220, 1989; L. Ratner, Nucleic Acid Research, 17:4101, 1989; J. Sodroski, et al., Science, 228:1430, 1985; J.E. Green, et al., Mol. Cell. Biol. 11:4635, 1991; S. J. Kim, et al., J. Exp. Med., 172:121, 1990; E. Bohnlein, et al., J. Virol., 63, 1578, 1988). In vitro studies of tax effects on gene expression, have demonstrated two independent pathways for its action on transcription (M. R. Smith and W. C. Green, J. Clin. Invest. 87:761, 1991). The first affects the family of nuclear transcription factors related to c-rel which bind to NF-xcexaB sites and are important for the normal activation of lymphocytes. NF-xcexaB response sequences occur in a number of genes including the HIV LTR (G. Nable, et al., Nature London, 326:711, 1987) and the IL-6 promoter (T. A. Libermann, et al., Mol. Cell. Biol., 10:2327, 1990). The heterodimer composed of the p5C and p65 rel related proteins have been shown to affect the transcription of many of these genes (P. A. Baeuerle, Biochem. Biophys. Acta, 1072:63, 1991). The other effect of tax is thought to be NF-xcexaB independent, whereby tax activates its own promoter through three tax responsive elements (TREs). Similar sequence motifs have been identified in fos (M. Fujii et al., Proc. Natl. Acad. Sci., USA, 85:8526, 1988), an immediate early response gene.
Unfortunately, although it is known that tax and other disorders appear linked to activation of NF-xcexaB, no therapeutic modalities exist which can suppress this activation and thereby inhibit progression or establishment of the disorder. The present invention addresses this need and provides composition and means of accomplishing this goal.
The present invention arose from the discovery that an antisense oligonucleotide which hybridizes to nuclear factor-xcexaB (NF-xcexaB) mRNA can be used to suppress processes which depend upon activation of NF-xcexaB.
As a consequence of this discovery, the present invention represents a major improvement over existing techniques for suppressing NF-xcexaB dependent processes which often entail use of chemicals which are highly toxic, especially in terms of their utilization in vivo. The antisense oligonucleotides of the invention display a high degree of biocompatibility with host systems such that the low efficiency and toxic aspects of prior art methodologies and compositions is avoided.

Suppression of nuclear factor-xcexab dependent processes using oligonucleotides


Large data sets can be stored and processed in real time by combining and registering the large data sets into a single data set. The data can be stored in a data tree structure formed of layers of spatially organized blocks of data. Such storage allows portions of the data to be viewed efficiently, displaying actual point data at an acceptable resolution for the viewing mechanism. Density limited queries can be executed that allow sub-sampling to be done directly and evenly without geometric constraint, to provide a subset of points that is limited in size and includes a spatially-even decomposition of that set of points. This allows the system as a whole to support arbitrarily large point sets while allowing full partitioning functionality, which is efficient to use in both time and space.

The acquisition of data and subsequent generation of computer models for real-world objects is of interest in many industries, for applications including architecture, physical plant design, entertainment applications (e.g., in movies and games), surveying, manufacturing quality control, medical imaging, and construction, as well as cartography and geography applications. In order to obtain accurate models of an object, as well as the area in which that object exists in the real world, it is necessary to take accurate measurements or samplings of surfaces that make up the object and any elements of the surrounding area. Historically, this sampling was carried out by surveyors, photogrammetrists, or technicians using techniques that provided samples at the rate of tens or hundreds per hour at most. Since the amount of data was relatively small, the data was easily dealt with in standard, off-the-shelf CAD programs or other modeling software.
Recent advances in technology such as LIDAR scanning technologies have resulted in the ability to collect billions of point samples on physical surfaces, over large areas, in a matter of hours. In a LIDAR process, a laser beam scans across a view that encompasses the structure of interest. The scanning device measures a large number of points that lie on surfaces visible in the scene. Each scan point has a measured location in 3D space, to within some measurement error, that typically is recorded relative to a point (x,y,z) in the local coordinate system of the scanner. The resulting collection of points is often referred to as one or more point clouds, where each point cloud can include points that lie on many different surfaces in the scanned view.
LIDAR systems are described, for example, in U.S. Pat. No. 5,988,862, filed Apr. 24, 1996, entitled "INTEGRATED SYSTEM FOR QUICKLY AND ACCURATELY IMAGING AND MODELING THREE DIMENSIONAL OBJECTS," which is hereby incorporated herein by reference. An exemplary LIDAR system 100 shown in FIG. 1 utilizes a Field Digital Vision (FDV) module 102 that includes a scanning sensor for scanning an object 104, such as a building of a piece of machinery. The scanning sensor also can sense the position in three-dimensional space of selected points on the surface of the object 104. The FDV module 102 generates a point cloud 106 that represents the sensed positions of the selected points. The point cloud 106 also can represent other attributes of the sensed positions, such as reflectivity, surface color, and texture, where desired.
A control and processing station 108 interacts with the FDV 102 to provide control and targeting functions for the scanning sensor. In addition, the processing and control station 108 can utilize software to analyze groups of points in the point cloud 106 to generate a model of the object of interest 104. A user interface 116 allows a user to interact with the system, such as to view a two-dimensional (2D) representation of the three-dimensional (3D) point cloud, or to select a portion of that object to be viewed in higher detail as discussed elsewhere herein. The processing station can include any appropriate components, such as standard computer and/or processing components. The processing station also can have computer code in resident memory, on a local hard drive, or in a removable drive or other memory device, which can be programmed to the processing station or obtained from a computer program product such as a CD-ROM or download signal. The computer code can include instructions for interacting with the FDV and/or a user, and can include instructions for undertaking and completing any modeling and/or scanning process discussed, described, or suggested herein.
The FDV 102 can include a scanning laser system (LIDAR) 110 capable of scanning points of the object 104, and that generates a LIDAR data signal that precisely represents the position in 3D space of each scanned point. The LIDAR data signal for the groups of scanned points can collectively constitute the point cloud 106. In addition, a video system 112 can be provided, which in one embodiment includes both wide angle and narrow angle CCD cameras. The wide angle CCD camera can acquire a video image of the object 104 and provides to the control and processing station 108, through a control/interface module 114, a signal that represents the acquired video image.
The acquired video image can be displayed to a user through a user interface 116 of the control and processing station 108. Through the user interface 116, the user can select a portion of the image containing an object to be scanned. In response to user input, the control and processing station can provide a scanning control signal to the LIDAR 110 for controlling the portion of the surface of the object that should be scanned by the LIDAR. More particularly, the scanning control signal can be used to control an accurate and repeatable beam steering mechanism that steers a laser beam of the LIDAR 110. The narrow angle CCD camera of the video system 112 can capture the intensity of the laser returned from each laser impingement point, along with any desired texture and color information, and can provide this captured information to the control and processing station 108. The control and processing station can include a data processing system (e.g., a notebook computer or a graphics workstation) having special purpose software that, when executed, instructs the data processing system to perform the FDV 102 control and targeting functions, and also to perform the model generation functions discussed elsewhere herein. Once the object has been scanned and the data transferred to the control and processing station, the data and/or instructions relating to the data can be displayed to the user. Alternatively, the user can select instructions before or during the LIDAR scan. If multiple scans are taken, these data sets can be registered to form a single data set, for a total number of points less than about 40 million for current technology, or can be registered but left as separate data sets for point sets larger than 40 million points, in order to allow the data to be loaded into a computer for processing and/or analysis. Current computer systems can only handle about 10 million points efficiently, but can handle up to about 40 million points inefficiently through compression techniques. Large octrees can be used in volumetric representations to store an approximation of the actual scan points, but the actual scan points are not available for processing. This simplification of the data can result in a loss of information and/or accuracy, and can cause problems when attempting to query the data.
Current scanning technologies can achieve sampling rates of up to 1 million points per second, with an accuracy of a few millimeters. While these advances can greatly increase the accuracy and complexity of the generated models, the advances also come with problems such as how to store, visualize, manipulate, and/or extract models and measurements from very large amounts of data, particularly where the vast amount of data cannot simply be loaded into computer memory, measured, partitioned, and modeled. For instance, individual data sets used to contain less than a million points but now can contain over 200 million points. Further, instead of tens of scans being taken of a physical object or structure it is now common to have on the order of 300-400 scans, greatly increasing the amount of data to be processed. Aggregate sample sets then can have tens of billions of data points. Current software can only compose data sets up to about 40 million points. For larger scans or data sets, the data is left uncomposed, or is reprocessed off-line into pieces no larger than about 40 million points, so that individual pieces can be worked with separately. The inability to easily process the data as a coherent whole is further complicated by the fact that data acquired by such scanners must undergo a series of processing steps to be used meaningfully, including the capture, registration, and fitting of the data.
The need for multiple data sets arises from the fact that most sensors providing the samples can only measure or detect a portion of the desired scan area from a given position. This is analogous to trying to get a full view of a three dimensional object with a camera. If the object can be moved, then a number of pictures must be taken from the single camera location in order to capture the entire object. If the object cannot be moved, the user must take multiple pictures from several different angles in order to have all of the surfaces of the object appear in at least one picture. Similarly, with sensor applications such as LIDAR applications, the sensor must often be moved to multiple locations in order to sample all sides or surfaces in a given target area. Since the various positions of the sensor generally are not known to any degree of certainty, it is necessary to determine how the sets of sensor samples from each position relate to each other. Without the proper relation information, it is impossible to generate a full sample set forming a coherent model of the entire object. In order to relate the data sets, a registration process must be undergone. Registering the data from multiple views is difficult and time consuming, in part because known techniques for registering sets of samples to each other do not work well on huge sample sets. Further, registration often requires intelligent decimation of those sets before the registration can take place. Existing systems cannot rapidly compute those intelligent decimations to accelerate registration operations.
Once the data sets are registered, it would be most efficient for the user be able to consider the samples to be in the same coordinate system and work with the data as a single, coherent whole. Unfortunately, the combination of many sample sets is often massive in size, and existing software packages still leave the individual sample sets separate in order to keep the size of any given set manageable. This separation leads to difficulty in measurement and fitting operations, as the user must manually cut and recombine small pieces of the sample sets together before being able to perform operations on the desired data segments. Further, managing the hundreds of data sets that are captured using existing systems can be overwhelming, particularly where each individual set is larger than can fit in memory. The size of the data sets can be addressed somewhat through existing data compression techniques (which presently can compress a data set by about 10%), but attempting to do data compression for a set containing 40 million data points, for example, can cause problems with system stability.
Another function which is problematic in existing systems is the partitioning of large data sets into smaller, coherent parts, typically referred to as data subsets. Users presently need to create subsets in order to do operations such as fitting. For example, the points corresponding to a pipe in a plant must sometimes be partitioned out from the rest of the data points for the plant in order to allow a geometric fit, or to copy the points for the pipe to another model in order to perform more detailed operations. Existing systems cannot efficiently support subset operations on large data sets, as these systems must do work proportional to the size of the components being cut in order to make that cut, then require space proportional to the size of the subset in order to store that subset.

System and method for efficient storage and manipulation of extremely large amounts of scan data


A motor vehicle window visor attachment that when affixed to visors will provide operators of vehicle with a handy place to store and log personal information pertinent to operator and geographic area where vehicle is most generally operated. A plastic pouch for storage of important papers, a writing instrument, advertising, a map, and an area on attachment that erasable notes may be written.

1. Field of Invention
This invention relates in general to motor vehicle window visor attachments. More particularly, the invention concerns a device which can be removably affixed to a motor vehicle window visor and provide vehicle operator a place to store and log personalized information useful to operator and the geographic area where vehicle is most generally operated. The invention will also provide a pouch to keep important papers, a writing instrument, and advertising messages.
2. Description of the Prior Art
Cellular phone use by business and the private sector is increasing rapidly. The cost of coupon and direct mail advertising is steadily increasing along with paper and printing expenses.
The prior art is replete with various types of automobile visor attachments. These prior art attachments typically include rather complex wallet-like or envelope devices having a number of pockets within which various articles can be placed. The devices are variously clipped, strapped, or otherwise removably connected to the visor. Generally, these devices are of a bulky make-up to use and typically are inordinately expensive to manufacture.
Examples of prior art visor attachments are those described in U.S. Pat. No. 5,379,929 (1994) and U.S. Pat. No. 5,516,018 (1995) issued to Eskandry; U.S. Pat. No. 5,402,924 (1994) issued to Gibson; and U.S. Pat. No. 4,034,910 (1976) issued to Rogers. As will better be appreciated from the discussion which follows, the visor attachment of the present invention simply provides operators of said vehicles with helpful information regarding emergency phone numbers, personal phone numbers, personal health information, oil change mileage information, a map, an erasable dry note pad with writing instrument, and a pouch to store vehicle registration and insurance papers.
The present invention will provide a venue for businesses to inexpensively advertise their goods and services right inside said vehicles, for the life of vehicle without incurring ongoing advertising paper and printing costs.
The present invention is easily affixed to vehicle visors and can be manufactured inexpensively which will be discussed in detail in the description of the preferred embodiment.


A traffic monitoring and notification system for vehicles includes road devices to be spaced apart along a road, and a traffic management controller. A portion of the vehicles may carry an electronic device that transmits an electronic address associated therewith. Each road device detects vehicles traveling on the road, determines if each detected vehicle is carrying an electronic device, and if so, then detects the electronic address associated therewith. A vehicle detection signal is transmitted based on each detected vehicle, and an electronic address signal is transmitted based on each detected electronic address. The traffic management controller receives the vehicle detection signals and the electronic address signals, determines a traffic pattern of the vehicles on the road based on the vehicle detection signals, and transmits a respective travel notification signal to each electronic device transmitting the electronic address associated therewith to provide travel information to a driver.

The flow of vehicle traffic has been studied extensively in the last few decades. Traffic control software including traffic based algorithms have been implemented to control the timing of traffic signal lights that regulate vehicle traffic.
A typical signalized intersection includes a traffic controller that is hard wired to the signal lights at the intersection for control thereof. The traffic controller includes algorithms for operating the signal lights. To more efficiently maintain the flow of traffic along a busy roadway with several signalized intersections, operation of the signal lights is coordinated among the traffic controllers associated therewith.
Efforts have been made to simplify the infrastructure used for monitoring and controlling signalized intersections. For example, U.S. Published Patent Application No. 2008/0074289 discloses a wireless traffic signal light management system. The system includes a master controller, wireless nodes dispersed in a geographic area and traffic signal lights also dispersed in the geographic area. The traffic signal lights are communicatively coupled to the master controller via the wireless nodes. Each wireless node is associated with a distinct Internet protocol address, and a wireless communication link provides Internet protocol based communications between the wireless nodes and the master controller. The wireless nodes receive control data packets for the communicatively coupled traffic signal lights from the master controller via the wireless communication link. The control data packets include the distinct Internet protocol address and operational instructions for at least one traffic signal light communicatively coupled to the wireless node, and each traffic signal light is responsive to the operational instructions in the control data packets.
Efforts have also been made to measure traffic flow by sampling a portion of actual travel times for vehicles in the traffic stream. Several cities in the United States, such as Houston and Boston, have been making measurements based on signals available from a point-to-point networking protocol commonly referred to as Bluetooth.
The majority of consumer electronic devices come equipped with Bluetooth wireless capability to communicate with other devices in close proximity. Bluetooth enabled devices can communicate with other Bluetooth enabled devices anywhere from 1 meter to about 100 meters, depending on the power rating of the Bluetooth devices. The Bluetooth protocol uses an electronic address, or tag, called a Media Access Control address, or MAC address.
A vehicle containing a detectable Bluetooth device is observed at successive detection stations. The MAC address and time of detection is logged, and the information is used to obtain an accurate sample of the travel time and an average speed. This type of information is generally used for measuring traffic flow.
There are other types of systems that provide traffic information to travelers via messages displayed on fixed road signs. The road signs are remotely programmable to provide messages about travel times and conditions on the roadway. A drawback of this approach is that the fixed road signs are expensive. Another drawback is that the travelers may already be on the road if the message being displayed is directed to an impending delay due to an accident.
Even in view of the advances made in traffic monitoring and traffic management, there is still a need to improve upon these activities.

Traffic monitoring and notification system and associated methods


A zipperless sleeping bag with a foldable flap for extra warmth and a method for making the same is provided. The sleeping bag consists of a substrate comprising three portions, a body portion, a first cover portion and a second cover portion each of which is characterized by a longitudinal and lateral length, the three portions having substantially equally lateral lengths. The first cover portion is folded over the body portion and fastened thereto along the bottom and at least a part of the side edge of the portions. At least a part of the second cover portion is folded over the first cover portion and body portion. The second cover portion serves either as a foldable flap which can be folded over the first cover portion to provide extra warmth or as the primary cover in more temperate sleeping conditions.

The present invention relates to a zipperless sleeping bag for use indoors or outdoors.
Conventional sleeping bags for camping purposes are composed of a lower cover and an upper cover, the upper cover fastened to the lower cover along the periphery of the upper cover and the periphery of the lower cover so as to form a pocket. U.S. Pat. No. 1,284,046 to Blocksom describes one such sleeping bag.
More recently blankets, comforters and sleeping bags have been disclosed in which first and optionally second side portions may be folded over a central body portion to envelope at least a portion of a human body. U.S. Pat. No. 4,534,065 to Comfort, U.S. Pat. No. 5,093,947 to Henegar et al. and U.S. Pat. No. 5,640,725 to Ando et al. are among many such disclosures.
Unfortunately, the side portions may slide off of the central portion as a result of movement on the part of a person resting within such blankets, comforters or sleeping bags. Even where fasteners are provided to prevent such an occurrence, it can be awkward for the resident of the bag to fasten the side portions, in particular at the bottom of the bag, without exiting the bag.
It is a goal of the present invention to provide a zipperless sleeping bag with foldable side portions which are at least partially affixed to the central body portion so as to form a pouch in which a person may rest. The inventive zipperless sleeping bag eliminates the need of the individual residing therein to fasten the side portions.


Device structures, design structures, and fabrication methods for a bipolar junction transistor. A first layer comprised of a first semiconductor material and a second layer comprised of a second semiconductor material are disposed on a substrate containing a first terminal of the bipolar junction transistor. The second layer is disposed on the first layer and a patterned etch mask is formed on the second layer. A trench extends through the pattern hardmask layer, the first layer, and the second layer and into the substrate. The trench defines a section of the first layer stacked with a section of the second layer. A selective etching process is used to narrow the section of the second layer relative to the section of the first layer to define a second terminal and to widen a portion of the trench in the substrate to undercut the section of the first layer.

The invention relates generally to semiconductor device and integrated circuit fabrication and, in particular, to fabrication methods, device structures, and design structures for a bipolar junction transistor.
Bipolar junction transistors may be utilized in integrated circuits designed for high-frequency applications and in integrated circuits designed for high-power applications such as power amplifiers. Generally, a bipolar junction transistor is comprised of three distinct semiconductor regions that define terminals, namely an emitter, a collector, and a base disposed between the emitter and collector. An NPN bipolar junction transistor includes a layer of p-type semiconductor material constituting the base and two layers of n-type semiconductor material constituting the emitter and collector. The layers of n-type semiconductor material are sandwiched between the two layers of n-type semiconductor material. The conductivity types of the semiconductor materials for the emitter, base and collector in a PNP bipolar junction transistor are reversed. Generally, the differing conductivity types of the emitter, base, and collector form a pair of p-n junctions, namely a collector-base junction and an emitter-base junction. A voltage applied across the emitter-base junction controls the movement of charge carriers between the collector and emitter.
Improved fabrication methods, device structures, and design structures are needed for a bipolar junction transistor.

Bipolar junction transistors with self-aligned terminals