Abstract: A bipolar transistor having base and collector regions of narrow bandgap semiconductor material and a minority-carrier excluding base contact has a base doping level greater than 1017 cm−3. The transistor has a greater dynamic range, greater AC voltage and power gain-bandwidth products and a lower base access resistance than prior art narrow band-gap bipolar transistors.

Abstract: A transistor with a novel compact layout is provided. The transistor has an emitter layout having a track with a first feed point and a second feed point whereby current flows through both the first feed point and the second feed point. A base terminal, a collector terminal, and an emitter terminal are provided. When in operation, current flows from the collector terminal to the emitter terminal based on the amount of current provided to the base terminal. A sub-collector layer is formed on a substrate. A collector layer is formed on the sub-collector layer. A base pedestal is formed on the collector layer. A base contact for coupling to the base terminal and an emitter is formed on the base pedestal. An emitter contact for coupling to the emitter terminal is formed on the emitter. A collector contact for coupling to the collector terminal is deposited in a trench that is formed in the collector layer and the sub-collector layer.

Abstract: The invention relates to a vertical bipolar transistor and a method for the production thereof. The aim of the invention is to produce a vertical bipolar transistor and to disclose a method for the production thereof, whereby excellent high frequency properties can be obtained for said transistor using the simplest possible production technology involving an implanted epitaxy-free collector and only one polysilicon layer spread over a large surface and which can be easily integrated into a conventional mainstream CMOS process without epitaxially produced trough areas.

Abstract: The invention includes a bipolar transistor construction having a collector region, emitter region, and base region extending within a semiconductive material substrate. The construction further comprises separate access regions associated with the base region, emitter region and collector region, respectively. An n-type doped connecting region is comprised by the collector region and extends beneath the emitter and base regions. A p-type doped location is comprised by the base region and extends beneath the emitter region and above the n-type doped connecting region. An n-type doped intermediate location is within the emitter region and between the p-type doped location and the emitter access region. The invention also includes methods of forming bipolar transistors.

Abstract: A semiconductor structure with greatly reduced backside chipping and cracking, as well as increased die strength, accommodation of compact assembly with a carrier such as another semiconductor chip, and resistance to package damage is provided by dicing chips from a wafer in a manner that chamfers edges of the chips. Similar advantages are obtained in multi-chip structure.

Abstract: An emitter of a heterojunction bipolar transistor has a double-layer protrusion formed of a first emitter layer and a second emitter layer and protruded outside an external base region. The protrusion of 50 nm in total thickness is enough to prevent damage during formation of the protrusion by etching or during later fabricating processes. Penetration of moisture through damaged places is eliminated. A base ohmic electrode is continuously formed on the first and second emitter layers on the external base region up to the protrusion. Thus, the protrusion is reinforced so as to be further hard to damage. By ensuring a large area for the base ohmic electrode, an alignment margin can be taken during formation of a base lead electrode.

Abstract: Various embodiments of a novel transistor layout having improved electrical and heat dissipation characteristics are disclosed. Several embodiments include various intrinsic components contoured to the shape of the emitter. The various intrinsic components may include a collector layer center portion, a collector contact, a base pedestal, and/or a base contact. Additional embodiments include improved heat dissipation within single transistors. Still further embodiments include improved heat dissipation across a plurality of transistors.

Abstract: A silicon-germanium base capable of use in heterojunction bipolar transistor includes a silicon substrate having a mesa surrounded by a trench. The mesa has a top surface and a silicon-germanium layer is disposed only on the top surface of the mesa. In addition, a heterojunction bipolar transistor includes the silicon-germanium base as described.

Abstract: A method for forming a self-aligned bipolar transistor includes the steps of combination etching a silicon substrate in an opening to form a concave surface on the silicon substrate, and forming an intrinsic base and an associated emitter on the concave surface. The combination etching includes an isotropic etching and subsequent wet etching. The concave surface increases the distance between the external base for the intrinsic base and the emitter to thereby increase the emitter-base breakdown voltage.

Abstract: A method of fabricating a bipolar transistor structure is provided in which a blanket silicon-germanium (SiGe) film is used in a self-aligned manner to form the active base region of the bipolar device, thereby eliminating the need for a complicated selective SiGe process.

Abstract: A differential negative resistance element includes a heavily doped GaAs layer interposed between a collector layer of lightly doped GaAs and an emitter layer of heavily doped AlGaAs, is shared between a base region between the collector layer and the emitter layer, a base contact region and a channel region between the base region and the base contact region, and a depletion layer is developed into the channel region together with the collector voltage so as to exhibit a differential negative resistance characteristics, wherein the channel region is formed through an epitaxial growth and etching so that the manufacturer easily imparts target differential negative resistance characteristics to the channel region.

Abstract: A heterojunction bipolar transistor includes an emitter or collector region of doped silicon, a base region including silicon-germanium, and a spacer. The emitter or collector region form a heterojunction with the base region. The spacer is positioned to electrically insulate the emitter or collector region from an external region. The spacer includes a silicon dioxide layer physically interposed between the emitter or collector region and the remainder of the spacer.

Abstract: A semiconductor device includes a semiconductor substrate, an electrode disposed on an upper surface of the substrate, and a transistor element disposed on the upper surface of the substrate. The transistor element continuously surrounds the electrode and includes a plurality of contacts that are electrically connected to the electrode. Additionally, the transistor element compactly surrounds the electrode with a threshold distance.

Abstract: A method and a structure of for an Electro Static Discharge (ESD) device that is silicided. There are three preferred embodiments of the invention. The first embodiment has a N/P/N structure. The emitter, the collector and the substrate form a parasitic transistor and the substrate is connected to the p+ diffusion region. The emitter and the substrate act as a first diode D1 and the collector and the substrate act as a second diode D2. The second embodiment has a first N+ well between a second n+ (collector) region and a P+ base region. The Vt1 is controlled by the dopant profiles of the P+ base and the n− first well where they intersect. The third embodiment is similar to the second embodiment, but the n− well covers all of drain. A parasitic NPN bipolar transistor comprises: an emitter, a parasitic base and a drain. The emitter is formed by the first n+ region. The parasitic base is formed by the p-substrate.

Abstract: According to a disclosed embodiment, a base region is grown on a transistor region. A dielectric layer is next deposited over the base region. The dielectric layer can comprise, for example, silicon dioxide, silicon nitride, or a suitable low-k dielectric. Subsequently, an opening is fabricated in the dielectric layer, and an emitter layer is formed on top of the dielectric layer and in the opening. Thereafter, an anisotropic polymerizing etch chemistry is utilized to etch the emitter layer down to a first depth, forming an emitter region in the opening. Next, a non-polymerizing etch chemistry having isotropic components is used to create a notch in the dielectric layer below the emitter region. The formation of the notch reduces the overlap area of a capacitor that forms between the emitter region and the base region, which translates to a lower level of emitter to base capacitance.

Abstract: The invention relates to a method of manufacturing a double heterojunction bipolar transistor (1) comprising successively at least one sub-collector layer, a collector layer, a base layer and a metallic layer (10) deposited on the said base layer; the said metallic layer (10) being extended towards a contact pad (110) of the base by an underetched metallic “air bridge” (100), characterized in that producing the said “air bridge” (100) includes the following steps: effecting a first localized etching under the said bridge, this first etching being selective so as to etch the sub-collector layer laterally; and effecting a second localized etching under the said bridge, this second etching being selective so as to vertically etch at least the collector layer.

Abstract: A highly miniaturized nanomechanical transistor switch is fabricated using a mechanical cantilever which creates a conductive path between two electrodes in its deflected state. In one embodiment, the cantilever is deflected by an electrostatic attraction arising from a voltage potential between the cantilever and a control electrode. In another embodiment, the cantilever is formed of a material with high magnetic permeability, and is deflected in response to complementary magnetic fields induced in the cantilever and in an adjacent electrode. The nanomechanical switch can be fabricated using well known semiconductor fabrication techniques, although semiconductor materials are not necessary for fabrication. The switch can rely upon physical contact between the cantilever and the adjacent electrode for current flow, or can rely upon sufficient proximity between the cantilever and the adjacent electrode to allow for tunneling current flow.

Abstract: A metallized structure for use in a microelectronic circuit is set forth. The metallized structure comprises a dielectric layer, an ultra-thin film bonding layer disposed exterior to the dielectric layer, and a low-Me concentration, copper-Me alloy layer disposed exterior to the ultra-thin film bonding layer. The Me is a metal other than copper and, preferably, is zinc. The concentration of the Me is less than about 5 atomic percent, preferably less than about 2 atomic percent, and even more preferably, less than about 1 atomic percent. In a preferred embodiment of the metallized structure, the dielectric layer, ultra-thin film bonding layer and the copper-Me alloy layer are all disposed immediately adjacent one another. If desired, a primary conductor, such as a film of copper, may be formed exterior to the foregoing layer sequence. The present invention also contemplates methods for forming the foregoing structure as well as electroplating baths that may be used to deposit the copper-Me alloy layer.

Abstract: Disclosed is a method for fabricating thin wafer insulated gate bipolar transistors (IGBTs), in which a portion on the back side of the device region is removed to form a hollow region with a depth that results in a device region thickness equivalent to the thickness of a thin wafer while the rest of the wafer remains its standard thickness. In other words, the method according to the present invention is suitable for the currently used wafer transfer stations under thin wafer conditions. The non-punch-through type insulated gate bipolar transistor (NPT-IGBT) fabricated with this method gets rid of an epi-layer and the “lifetime killer” process. The punch-through type insulated gate bipolar transistor (PT-IGBT) fabricated with this method has higher switching efficiency due to reduced injection efficiency of the p+-type minority carriers.

Abstract: Providing a method of producing a semiconductor device and a structure of the semiconductor device employing a trench isolation structure for isolating semiconductor elements wherein volumetric expansion of a trench-filling material due to oxidation process after forming the trench isolation structure is controlled thereby making it possible to prevent deterioration of the electrical characteristics of the semiconductor device. A nitriding treatment is applied to the trench surface of the silicon substrate after forming the trench by etching, thereby to form a thin nitride layer having a better effect of preventing oxidation in the interface of silicon.

Abstract: A semiconductor process is disclosed which forms openings in a dielectric layer through which the base region of both high-voltage and high-gain bipolar transistors are formed. In one embodiment of the invention, the openings for the high-gain transistors are first protected by a photoresist layer that is patterned to expose the openings for the high-voltage transistors. A first base implant is performed through the exposed windows in the dielectric layer and into the exposed substrate or epitaxial layer therebelow, and then diffused to a suitable depth. The patterned photoresist is then removed to additionally expose the openings for the high-gain devices, and a second base implant is performed, this time into both base regions, and then diffused to a suitable depth. Emitter regions are then formed within the base regions of both transistor types by traditional implantation and contact techniques.

Abstract: A process for forming a microelectromechanical system (MEMS) device by a deep reactive ion etching (DRIE) process during which a substrate overlying a cavity is etched to form trenches that breach the cavity to delineate suspended structures. A first general feature of the process is to define suspended structures with a DRIE process, such that the dimensions desired for the suspended structures are obtained. A second general feature is the proper location of specialized features, such as stiction bumps, vulnerable to erosion caused by the DRIE process. Yet another general feature is to control the environment surrounding suspended structures delineated by DRIE in order to obtain their desired dimensions. A significant problem identified and solved by the invention is the propensity for the DRIE process to etch certain suspended features at different rates.

Abstract: A method of forming an NPN semiconductor device includes the steps of forming a collector region within a substrate, forming a base region over the collector region, and forming an oxide-nitride-oxide stack over the base region. Once these three structures are formed, an opening is created through the oxide-nitride-oxide stack to expose the top surface of the base region. Then, a doped polysilicon material is used to fill the opening and make electrical contact to the base region. The use of the oxide-nitride-oxide stack with appropriate etching of the opening eliminates the exposure of the base region to reactive ion etch environment typical of prior art methods for forming NPN semiconductor devices. As an option, after the opening of the oxide-nitride-oxide stack is formed, a local oxidation of silicon (LOCOS) and etched can be preformed to create oxide spacers to line the opening wall above the base region.

Abstract: A heterojunction bipolar transistor includes an emitter or collector region of doped silicon, a base region including silicon-germanium, and a spacer. The emitter or collector region form a heterojunction with the base region. The spacer is positioned to electrically insulate the emitter or collector region from an external region. The spacer includes a silicon dioxide layer physically interposed between the emitter or collector region and the remainder of the spacer.

Abstract: A method for fabricating complementary vertical bipolar junction transistors of silicon-on-sapphire in fewer steps than required for true complimentary vertical bipolar junction transistors is disclosed. Initially a thin layer of silicon is grown on a sapphire substrate. The silicon is improved using double solid phase epitaxy. The silicon is then patterned and implanted with P+-type and N+-type dopants. Subsequently a micrometer scale N-type layer is grown that acts as the intrinsic base for both an PNP transistor and as the collector for an NPN transistor. The extrinsic base for the NPN is then formed and the emitter, collector and ohmic contact regions are next selectively masked and implanted. Conductive metal is then formed between protecting oxide to complete the complementary vertical bipolar junction transistors.

Abstract: An insulated-gate bipolar switch contains a number of trench-IGBT structures interdigitated with a number of floating mesas and trench gates to reduce inversion channel density. The IGBT mesa widths and the floating mesa widths are made different, which enables the switch to provide desired VFD, SCSOA and RBSOA values. The mesa widths and the number of floating mesas per unit cell are adjusted as needed to provide a switch having desired characteristics.

Abstract: A metallized structure for use in a microelectronic circuit is set forth. The metallized structure comprises a dielectric layer, an ultra-thin film bonding layer disposed exterior to the dielectric layer, and a low-Me concentration, copper-Me alloy layer disposed exterior to the ultra-thin film bonding layer. The Me is a metal other than copper and, preferably, is zinc. The concentration of the Me is less than about 5 atomic percent, preferably less than about 2 atomic percent, and even more preferably, less than about 1 atomic percent. In a preferred embodiment of the metallized structure, the dielectric layer, ultra-thin film bonding layer and the copper-Me alloy layer are all disposed immediately adjacent one another. If desired, a primary conductor, such as a film of copper, may be formed exterior to the foregoing layer sequence. The present invention also contemplates methods for forming the foregoing structure as well as electroplating baths that may be used to deposit the copper-Me alloy layer.

Abstract: In a bipolar transistor improved to exhibit an excellent high-frequency property by decreasing the width of the intrinsic base with without increasing the base resistance, an emitter region, intrinsic base region and collector region are closely aligned on an insulating layer, and the intrinsic base region and the collector region make a protrusion projecting upward from the substrate surface. The protrusion has a width wider than the width of the intrinsic base region.

Abstract: The invention relates to a semiconductor device comprising a bipolar transistor having a collector (1), a base (2) and an emitter (3) at its active area (A). The semiconductor body (10) of the device is covered with an insulating layer (20). At least a part of a base connection conductor (5) and an emitter connection conductor (6) extend over the insulating layer (20) and lead to a base connection area (8) and an emitter connection area (9), respectively. The known transistor is characterized by poor gain, particularly at high frequencies and at high power.

Abstract: The present invention relates to a pinned photodiode used in a CMOS image sensor. The pinned photodiode according to the present invention has an uneven surface for increasing an area of a PN junction of the photodiode. So, the increased PN junction area improves a light sensitivity of the photodiode. That is, the epitaxial layer, in which the photodiode is formed, has a trench or a protrusion. Also, in the pinned photodiode, since the P0 diffusion layer is directly in contact with the P-epi layer, the two P-type layers have the same potential and then it may operate in a low voltage.

Abstract: A semiconductor includes a buried conducting layer, such as a buried collector, comprises a trench, the walls of which are covered with a layer of a material in which dopant ions diffuse faster than in monocrystalline silicon. A contact area is doped in close proximity to the trench wall. The dopants will diffuse through the layer and form a low resistance connection to the buried layer. The layer may comprise polysilicon or porous silicon, or a silicide. If the material used in the layer is not in itself conducting, the size of the component may be significantly reduced.

Abstract: A bipolar transistor having at least a low doped drift layer (14) of crystalline SiC comprises at least one first layer (13) of a semi-conductor material having a wider energy gap between the conduction band and the valence band than an adjacent layer (14) of SiC.

Abstract: A semiconductor device includes: a semiconductor layered structure including a predetermined mesa portion, formed on a semiconductor substrate; a support member formed so as to bury the mesa portion; and an interconnection layer formed on a top surface of the semiconductor layered structure so as to extend over a top surface of the support member. The interconnection layer is in contact with only a top surface of the mesa portion without being in contact with a bottom surface of the mesa portion. The top surface of the support member has a smoothed profile, and the top surface of the mesa portion and the smoothed top surface of the support member are in substantially the same plane.

Abstract: A heterojunction bipolar transistor based on the InP/InGaAs materials family and its method of making. An n-type collector layer, principally composed of InP is epitaxially grown on an insulating InP substrate by vapor phase epitaxy. The collector layer is then laterally defined into a stack, and semi-insulating InP is regrown around the sides of the stack to the extent that it planarizes with the stack top. The semi-insulating InP electrically isolates the collector stack. A thin base layer of p-type InGaAs, preferably lattice matched to InP, is grown over the collector stack, and n-type emitter layer is grown over the base layer. A series of photolithographic steps then defines a small emitter stack and a base that extends outside of the area of the emitter and collector stacks. The reduced size of the interface between the base and the collector produces a lower base-collector capacitance and hence higher speed of operation for the transistor.

Abstract: A method for making self-aligned sub-micrometer bipolar transistors and FETs on a substrate for BiFET and BiCMOS circuits was achieved using a novel LOCOS structure as a self-aligned implant mask. This LOCOS structure uses a silicon nitride mask comprised of stripes with well defined widths and spacings to form a punchthrough oxide mask of varying thicknesses over the emitter, base, and collector of the bipolar transistor, while providing a thick field oxide elsewhere on the substrate. The oxide mask serves as a self-aligned implant mask for implanting the emitter, base, and collector of the bipolar transistor. The nitride mask can be patterned concurrently to form an implant mask for the FET. A series of ion implants is then used to form the emitter, base, and collector without requiring separate photoresist masks. An array of nitride stripes with well defined widths and spacings can be used to make larger transistors, such as bipolar power transistors.

Abstract: A heterojunction bipolar transistor and its fabrication method is disclosed. The heterojunction bipolar transistor includes a substrate; a collector layer formed to have a ledge or MESA on the substrate; a collector electrode formed on the collector layer surrounding the ledge; a base layer formed on the ledge of the collector layer; an ohmic cap layer on the emitter layer; an emitter layer formed in the center of the base layer; an emitter electrode formed on the ohmic cap layer; a base electrode formed on the base layer surrounding the emitter electrode; an insulating layer formed to cover the base electrode and to overlay on the insulating layer; a metal wire formed to cover the emitter electrode; and an air bridge brought in contact with the metal wire and electrically connected to an external pad lying on an ion-implanted isolation region.

Abstract: This invention describes fabrication procedures to construct MEMS devices, specifically band-pass filter resonators, in a manner compatible with current integrated circuit processing. The final devices are constructed of single-crystal silicon, eliminating the mechanical problems associated with using polycrystalline silicon or amorphous silicon. The final MEMS device lies below the silicon surface, allowing further processing of the integrated circuit, without any protruding structures. The MEMS device is about the size of a SRAM cell, and may be easily incorporated into existing integrated circuit chips. The natural frequency of the device may be altered with post-processing or electronically controlled using voltages and currents compatible with integrated circuits.

Abstract: A transistor with a novel compact layout is provided. The transistor has an emitter layout having a track with a first feed point and a second feed point whereby current flows through both the first feed point and the second feed point. A base terminal, a collector terminal, and an emitter terminal are provided. When in operation, current flows from the collector terminal to the emitter terminal based on the amount of current provided to the base terminal. A sub-collector layer is formed on a substrate. A collector layer is formed on the sub-collector layer. A base pedestal is formed on the collector layer. A base contact for coupling to the base terminal and an emitter is formed on the base pedestal. An emitter contact for coupling to the emitter terminal is formed on the emitter. A collector terminal for coupling to the collector contact is deposited in a trench that is formed in the collector layer and the sub-collector layer.

Abstract: A compound semiconductor device having a mesa type heterojunction bipolar transistor comprises a collector layer of first conductivity type having a collector breakdown voltage of a predetermined magnitude, a base layer of second conductivity type formed on the collector layer, an emitter layer of first conductivity type formed on the base layer, and a subcollector layer of first conductivity formed in a region remote laterally from an edge of the base layer to be connected to the collector layer.

Abstract: A ballasted transistor structure reduces thermal runaway. A heterojunction bipolar junction transistor array includes a plurality of transistors, each having an emitter, a base and a collector. Each of the bases is an alloy of silicon and germanium and each of the collectors and emitters is silicon. A ballast resistor, of doped silicon, that prevents thermal runaway, is electrically connected to each of the collectors.

Abstract: A semiconductor device provided with a wide and shallow first groove and a second groove in the first groove area, having a narrower width than that of the first groove around a predetermined area in a one-conductive area provided in the upper region of a semiconductor substrate as a mesa groove, wherein at least the second groove is covered with an electrical insulator. The upper surface of the electrical insulator is located approximately as high as or lower than the upper surface of the electrical insulating film. Thus, especially in a mesa semiconductor device with a high-voltage resistance, an insulating protective layer having a sufficient thickness can be formed stably over the entire region of a mesa groove. As a result, the variation in high-voltage resistance characteristics can be decreased and the processing yield affected by breakage or cracking in the mesa groove region during subsequent processes caused by the formation of the mesa groove can be improved greatly.

Abstract: On an n-type semiconductor substrate 41 doped in high density, a p-type semiconductor layer 2, an n-type semiconductor layer 4 doped in high density, which is a collector, a p-type semiconductor layer 6 doped in high density, which is a base, and the n-type semiconductor layer 7, which is an emitter, are sequentially stacked. To the collector layer, a collector electrode 12 is electrically connected, and to the base layer, a base electrode 11 is electrically connected, and to the emitter layer, an emitter electrode 9 is electrically connected, and thus a bipolar transistor is structured. On the bipolar transistor, an insulated isolation area 55 is formed with an opening therein, whose depth reaches the surface of the substrate, and a substrate electrode 48 is formed thereon. On the bipolar transistor and the insulated isolation area 55, an inter-layer dielectric layer 54 is formed having contact holes formed to upper parts of the emitter electrode 49 and to the substrate electrode 48.

Abstract: A semiconductor device (10) is formed in a pedestal structure (16) overlying a semiconductor substrate (11). The semiconductor device (10) includes a base region (44) that contacts the corners (13) of the pedestal structure (16). Electrical connection to the base region (44) is provided by a conductive layer (28) that contacts the sides (12) and corners (13) of the pedestal structure (16).

Abstract: The present invention relates to an integrated circuit including a lateral well isolation bipolar transistor. A first portion of the upper internal periphery of the insulating well is hollowed and filled with polysilicon having the same conductivity type as the transistor base, to form a base contacting region. A second portion of the upper internal periphery of the insulating well is hollowed and filled with polysilicon having the same conductivity type as the transistor emitter, to form an emitter contacting region.

Abstract: A photoresist pattern is formed on a field oxide film and an element forming region across the field oxide film and the element forming region such that a portion of a surface of the field oxide film and a portion of a surface of a silicon epitaxial layer are continuously exposed. The photoresist pattern is used as a mask to inject boron ions into the silicon epitaxial layer and heat treatment is performed thereon to form an external base containing the relatively significant crystal defect present in the silicon epitaxial layer in the vicinity of the field oxide film. Thus, a semiconductor device can be obtained including a bipolar transistor which provides improved breakdown voltage between the collector and the base and contemplates reduction of current leakage.

Abstract: A heterojunction bipolar transistor has a mesa including collector 604, base 603, and emitter 602 layers. The mesa has first and second sidewalls 606. An improved heat dissipation structure comprises a layer of electrically insulative and thermally conductive material 607 disposed on one of the sidewalls. A thermal path metal 600 is electrically connected to the emitter 602 and is disposed on the layer of electrically insulative and thermally conductive material 607. The thermal path metal 600 extends from the emitter 602 to the substrate 608 providing for efficient dissipation of heat that is generated by the HBT device.

Abstract: A micromachined insulative carrier substrate preferably formed of silicon and a multi-chip module formed from the micromachined substrate. The micromachined substrate is fabricated by forming mesas across the surface of the substrate, forming an insulating layer on the substrate, and forming conductive traces on the insulating layer to route signals between semiconductor dice and/or to external circuitry. A variety of semiconductor dice and/or integrated circuitry-bearing wafer configurations (collectively, "semiconductor elements") may be attached to the semiconductor substrate. Electrical contact between the carrier substrate and semiconductor element is achieved with conductive connectors formed on either the semiconductor element or the carrier substrate. The conductive connectors each preferably make contact with both a portion of the conductive trace extending down the sidewall of the mesa and a portion of the conductive trace on the substrate between the mesas to form a more effective bond.

Abstract: In a bipolar transistor including a semi-insulating substrate, a collector layer formed on the semi-insulating substrate and a base layer formed on the collector layer, a base contact layer is in contact; with a part of a lower surface of the base layer.

Abstract: A semiconductor device having a Schottky gate and a bipolar device. A semiconductor substrate has a surface layer in ohmic contact with the conductor and the deeper layer in Schottky contact with the conductor. The substrate has a recess which reaches into the deeper layer. A conductor field extends from the bottom of the recess in a direction perpendicular to the bottom. Insulating films are formed on both vertical surfaces of the conductor film. Another conductor film is formed across the top of the first conductor film and both insulating films. Conductor films are formed on the surface of the substrate on either side of the insulating films. In this device, the electrode length/width is reduced and the response to the element is improved. Further, because the second conductor film is formed on the first conductor film, it is possible to reduce the gate electrode and the base electrode.

Abstract: In an integrated heterojunction bipolar transistor (HBT) with minimized base-collector capacitance, a sub-collector region is formed as a mesa on a substrate, a collector contact is to the sub-collector mesa region, a lightly-doped collector region and a base region extend from the mesa onto the substrate, and a base contact and its via hole for interconnection are off the mesa, with minimal overlap with the sub-collector region. The latter may be termed a buried selective sub-collector (BSSC) region. Such transistors can be used as integrated switching devices and microwave devices, e.g., in wireless communications, satellite direct broadcast systems, automobile collision avoidance systems, global positioning systems, and other high-frequency applications.