Abstract: As external connection terminals for an emitter electrode (12) of an IGBT chip, a first emitter terminal (151) for electrically connecting a light emitter in a strobe light control circuit to the emitter electrode (12) and a second emitter terminal (152) for connecting a drive circuit for driving an IGBT device to the emitter electrode (12) are provided. The first emitter terminal (151) and the second emitter terminal (152) are individually connected to the emitter terminal (12) by wire bonding.

Abstract: An n-type low impurity concentration semiconductor layer is provided, by epitaxial growth or the like, on a p-type semiconductor substrate. In order to vertically form a semiconductor device in the low impurity concentration semiconductor layer, at least a p-type diffusion region is provided. In a surface of the semiconductor layer, a collector electrode and a base electrode are respectively formed in electrical connection to the n-type low impurity concentration semiconductor layer and the p-type diffusion region. The collector electrode is formed on a surface of the n+-type low resistance region of a polycrystal semiconductor formed depthwise in the low impurity concentration semiconductor layer.

Abstract: A transistor includes a substrate region (14) of a first type (P) of conductivity in a semiconductor material layer of the same type (P) of conductivity, at least a first contact region (13) of the first type (P+) of conductivity inside the substrate region (14) and adjacent to a first terminal (C) of the transistor, a well (11) of second type (N) of conductivity placed inside the substrate region (14), wherein the well (11) of second type (N) of conductivity includes at least a second contact region (12) of a second type of conductivity (N+) adjacent to a region of a second terminal (B) of the transistor, and a plurality of third contact regions (10) of the first type of conductivity (P+) adjacent to a plurality of regions of a third terminal (E1, . . . , E3) of the transistor interposed each one (10) and other (12) by proper insulating shapes (20).

Abstract: A Pt alloyed reaction layer is formed under a base ohmic electrode. This alloyed reaction layer extends through a base protective layer so as to reach a base layer. Besides, a Pt alloyed reaction layer is formed under an emitter ohmic electrode. This alloyed reaction layer is formed only within a second emitter contact layer. With this constitution, the manufacturing cost for the HBT can be reduced and successful contact characteristics for the HBT can be obtained.

Abstract: An ESD protective transistor comprises a heavily doped p-type base region which is arranged in a lightly doped p-well and which is provided with a first terminal. Furthermore, a heavily doped n-type emitter region is arranged in the lightly doped p-well. A heavily doped n-type collector region is separated from the lightly doped p-well through a lightly doped n-type region and is provided with a second terminal. The heavily doped n-type emitter region is not short-circuited with the heavily doped base region viy a common electrode and is of floating design. The doping types of the respective regions may be reversed.

Abstract: An object of the invention is to minimize variation in characteristics of a vertical bipolar transistor. An insulating side wall spacer composed of a silicon nitride film 10 and a silicon oxide film 9 is formed on the side surface of an opening 101 formed in a base electrode polysilicon film 7. The thickness (=WD) of the insulating side wall spacer is made thicker than the maximum thickness (=WF) within a range of variation in thickness of a polycrystalline film 12 grown from the side surface of the base electrode polysilicon film 7 exposed inside the opening 101 (namely, WD>WF). The size of an opening for forming an emitter electrode polysilicon film 16 on an intrinsic base 11 is not influenced by the thickness of a polycrystalline film 12 epitaxially growing from the side surface of the polysilicon film 7 for the base electrode, but is defined by the side wall spacer formed on a portion of the side surface of the base electrode polysilicon film.

Abstract: A method for adjusting the gain or the sensitivity of a lateral component formed in the front surface of a semiconductor wafer, having a first conductivity type, includes not doping or overdoping, according to the first conductivity type, the back surface when it is desired to reduce the gain or sensitivity of the lateral component, and doping according to the second conductivity type, the back surface, when the gain or the sensitivity of the lateral component is to be increased.

Abstract: A Si1-xGex layer 111b functioning as the base composed of an i-Si1-xGex layer and a p+ Si1-xGex layer is formed on a collector layer 102, and a Si cap layer 111a as the emitter is formed on the p+ Si1-xGex layer. An emitter lead electrode 129, which is composed of an n− polysilicon layer 129b containing phosphorus in a concentration equal to or lower than the solid-solubility limit for single-crystal silicon and a n+ polysilicon layer 129a containing phosphorus in a high concentration, is formed on the Si cap layer 111a in a base opening 118. The impurity concentration distribution in the base layer is properly maintained by suppressing the Si cap layer 111a from being doped with phosphorus (P) in an excessively high concentration. The upper portion of the Si cap layer 111a may contain a p-type impurity. The p-type impurity concentration distribution in the base layer of an NPN bipolar transistor is thus properly maintained.

Abstract: A three axis MEM tunneling/capacitive sensor and method of making same. Cantilevered beam structures for at least two orthogonally arranged sensors and associated mating structures are defined on a first substrate or wafer, the at least two orthogonally arranged sensors having orthogonal directions of sensor sensitivity. A resonator structure of at least a third sensor is also defined, the third sensor being sensitive in a third direction orthogonal to the orthogonal directions of sensor sensitivity of the two orthogonally arranged sensors and the resonator structure having a mating structure thereon. Contact structures for at least two orthogonally arranged sensors are formed together with mating structures on a second substrate or wafer, the mating structures on the second substrate or wafer being of a complementary shape to the mating structures on the first substrate or wafer.

Abstract: Disclosed is a method of fabricating a lateral semiconductor device, comprising: providing a substrate, having at least an upper silicon portion forming at least one first dopant type region and at least one second dopant type region in the upper portion of the substrate, at least one of the first dopant type regions abutting at least one of the second dopant type regions and thereby forming at least one PN junction; and forming at least one protective island on a top surface of the upper silicon portion, the protective island extending the length of the PN junction and overlapping a portion of the first dopant type region and a portion of an abutting second dopant type region.

Abstract: A bipolar transistor having a base contact surrounded by an emitter contact. A plurality of wires extending from the base contact and the emitter contact of the bipolar transistor, wherein the wires of the base contact are stacked higher than the wires of the emitter contact. A device comprising a plurality of these bipolar transistors, wherein at least one side of each emitter contact abuts each adjacent transistor. Increasing the wiring stack of each row of transistors in the device as the distance between the row and the current input increases.

Abstract: A vertical bipolar transistor includes a semiconductor substrate, an extrinsic collector layer in the semiconductor substrate, an intrinsic collector on the extrinsic collector, a lateral isolating region surrounding an upper part of the intrinsic collector, an offset extrinsic collector well, a base including a semiconductor region above the intrinsic collector and above the lateral isolating region including at least one silicon layer, and a doped emitter surrounded by the base. The doped emitter may include first and second parts. The first part may be formed from single-crystal silicon and in direct contact with the upper surface of the semiconductor region in a predetermined window in the upper surface above the intrinsic collector. The second part may be formed from polycrystalline silicon. The two parts of the emitter may be separated by a separating oxide layer spaced apart from the emitter-base junction of the transistor.

Abstract: A semiconductor device includes a semiconductor substrate, an electrode disposed on an upper surface of the substrate, and a set of one or more transistor element(s) disposed on the upper surface of the substrate. The set of transistor element(s) compactly surrounds the electrode with a threshold distance. In one embodiment, the set also compactly surrounds a via hole. In another, the element(s) comprises a bipolar junction transistor that has an aggregate emitter length of not less than 10 microns. In still another embodiment, the device is coupled to a RF circuit for power amplification.

Abstract: A heterojunction bipolar transistor includes an emitter layer, a base layer and a collector layer laminated on a top surface of a semiconductor substrate, and a heat sink layer made of a metal and provided on a rear surface of the substrate. A via hole is cut through the emitter layer, the base layer, the collector layer and the substrate. A surface electrode of the emitter layer and the heat sink layer are connected to each other by a metal wiring line running through within the via hole, which is capable of improving the heat radiation and reducing the emitter inductance.

Abstract: A lateral bipolar transistor for an intergrated circuit is provided that maintains a high current gain and high frequency capability without sacrificing high Early voltage. More particularly, a lateral bipolar transistor is formed on an integrated circuit having both bipolar and CMOS devices, the lateral bipolar transistor being formed according to the BiCMOS method and without additional steps relative to formation of vertical bipolar devices if provided in the same area. Among other things, an integrated circuit is provided in which P well structures are provided in the collector regions of an LPNP that have been found to affect a significant increase in the product of the Early voltage and the current gain.

Abstract: A method and structure for a bipolar transistor with a semiconductor substrate having a surface and a shallow trench isolation (STI) in the surface. The STI has an edge, a crevice region in the STI adjacent the STI edge, a base region above the STI, a silicide above the base region, an emitter structure on the surface adjacent the base region, and a crevice cover between the emitter structure and the silicide. The crevice cover maintains spacing between the emitter structure and the silicide.

Abstract: An insulated gate transistor comprising a first semiconductor region, a second semiconductor region includes plural portions, a third semiconductor region, a fourth semiconductor region, a first insulation layer, control electrodes, a first main electrode, and a second main electrode, wherein a metallic wiring layer is provided on the first main surface plane via an insulating layer, plural regions insulated from the first main electrode are provided through said first main electrode, and the metallic wiring layer is connected electrically to the control electrode through the insulating layer via the region insulated from the main electrode.

Abstract: A lateral heterojunction bipolar transistor comprises a first semiconductor layer in a mesa configuration disposed on an insulating layer, a second semiconductor layer formed by epitaxial growth on the side surfaces of the first semiconductor layer and having a band gap different from that of the first semiconductor layer, and a third semiconductor layer formed by epitaxial growth on the side surfaces of the second semiconductor layer and having a band gap different from that of the second semiconductor layer. The first semiconductor layer serves as a collector of a first conductivity type. At least a part of the second semiconductor layer serves as an internal base layer of a second conductivity type. At least a part of the third semiconductor layer serves as an emitter operating region of the first conductivity type. The diffusion of an impurity is suppressed in the internal base formed by epitaxial growth.

Abstract: The fabrication process comprises a phase of producing a base region having an extrinsic base and an intrinsic base, and a phase of producing an emitter region comprising an emitter block having a narrower lower part located in an emitter window provided above the intrinsic base. Production of the extrinsic base comprises implantation of dopants, carried out after the emitter window has been defined, on either side of and at a predetermined distance dp from the lateral boundaries of the emitter window, so as to be self-aligned with respect to this emitter window, and before the emitter block is formed.

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: An electrode wiring structure is disclosed which realizes a semiconductor apparatus as a power semiconductor module with the current path set as shortest as possible and uniformly. The semiconductor apparatus includes: a plurality of semiconductor devices mounted in one array or more on a substrate; a main current electrode mounted along the array(s) of the semiconductor devices, and commonly connected to each of the plurality of semiconductor devices through the substrate. The substrate is connected to the main current electrode through a plurality of wires arranged along the array(s) at equal or substantially equal distances.

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 first insulating film 4 having a first opening portion is formed on an emitter region 10 and a second insulating film 6 having a second opening portion smaller than the first opening portion is formed on the first insulating film 4. The first and second opening portions are buried with emitter electrode material 9 doped with impurities.

Abstract: The present invention relates to a collector pin and a trench in an integrated circuit intended for high speed communication, and to a manufacturing method for these items. The collector pin is achieved by creating an area which is implantation damaged or made amorphous and at least partially doped (139) by means of ion implantation from an upper silicon surface comprised in a semiconductor structure (144) down to a depth lower than the depth of the surrounding field oxide (120), and that the semiconductor structure (144) is then heat treated.

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 radio-frequency (RF) integrated circuit is described. In one embodiment, the IC comprises multiple metal layers forming multiple transistors on a non-epitaxial substrate. The transistors are step and mirror symmetric. Also, the RF signal lines are on a top metal layer above all other metal layers and the power and ground planes are on a bottom metal layer below all other metal layers. The top and bottom metal layers are separated by a shield that extends beyond the RF signal lines by a distance that is at least the same distance that the shield is away from the RF lines. Low frequency signals are on signal lines below the top metal layer.

Abstract: It is an object to provide an insulating film which enables not only to obtain a good film quality but to achieve an excellent filling property, thick film formation and planarization simultaneously, and to provide an insulating film forming coating solution for forming the insulating film, and to provide a method of manufacturing the insulating film.

Abstract: Provided is a BiCOMOS semiconductor integrated circuit device which comprises a semiconductor substrate having an insulating layer internally and partially embedded therein and a semiconductor layer deposited on the insulating layer, an insulated gate type transistor formed in the semiconductor layer, a highly-doped collector layer of a bipolar transistor embedded in an insulating-layer-free portion of the semiconductor substrate, and a low-doped collector layer disposed on the highly-doped collector layer of the bipolar transistor, wherein the height level of the lower portion of the low-doped collector layer is below the height level of the lower portion of the insulating layer so as to attain high breakdown voltage and high speed operation of the bipolar transistor.

Abstract: The device is constituted by an N+ substrate, by an N− layer on the substrate, by a metal contact for a collector, by a buried P− base region, by a P+ base contact and insulation region within which an insulated N region is defined, by a metal contact on the base contact region for a base, by an N+ emitter region buried in the insulated region and forming a pn junction with the buried base region, by a P+ body region in the insulated region, by an N+ source region in the P+ region, by a metal contact for a source, and by a gate electrode. In order to achieve a low resistance Ron, the P+ body region extends as far as the buried N+ emitter region and an additional N+ region is provided within the body region and constitutes a drain region, defining, with the source region, the channel of a lateral MOSFET transistor.

Abstract: The breakdown voltage of a semiconductor device, such as a transistor fabricated in a device region in and abutting the surface of a semiconductor body with a field oxide surrounding the device region, is improved by etching the field oxide abutting the device region to reduce the thickness thereof to about 0.6-1.4 &mgr;m and then forming a field plate in the recessed field oxide which is capacitively coupled to the underlying semiconductor body. The field plate can be floating, connected to a voltage potential, or connected to the semiconductor device.

Abstract: Lateral bipolar transistor, in which a thin diffusion barrier (4) is applied to a base region (10) between an emitter region (9) and a collector region (11), and there is present, on said barrier, a base electrode (8) which is provided for low-resistance supply, is connected to a heavily doped base terminal region and consists of polysilicon, for example, into which dopant is diffused out from said base terminal region.

Abstract: Expansion promotion means (24) for more efficiently promoting the expansion of the depletion layer (19) than the electrically insulating film(14) having a suppressor electrode layer (20) buried therein is arranged between narrow portions (23b) of the suppressor electrode layer to control the expansion of the depletion layer (19), by which arrangement the spacing s between the narrow portions (23b) can be reduced without decreasing the field reducing effect of the field reduction means, which contains the suppressor electrode layer.

Abstract: A three layer IGBT which cannot latch on is provided with a trench gate and a Schottky contact to the depletion region surrounding the trench gate. An emitter contact is connected to base diffusion regions which are diffused into the depletion region. The depletion region is formed atop an emitter region which emits carriers into the depletion region in response to the turn on of the gate and the injection of carriers from the Schottky gate.

Abstract: High frequency performance of transistor designs is enhanced and manufacturing yield improved by removing and reducing sources of parasitic capacitance through combinations of processes from different technologies. After formation of collector, base and emitter regions on a substrate and attachment of a second substrate, the original substrate is wholly or partially removed, the inactive collector area is removed or rendered semi-insulating and wiring and contacts are made from the original back side of the chip. Dielectric material used in the manufacturing process can be removed to further reduce capacitance. The high frequency transistors can be bonded to CMOS chips or wafers to form BICMOS chips.

Abstract: An insulated gate bipolar transistor having a collector electrode 3, an emitter region 6 and a base region 4 formed between the collector electrode and the emitter region, further including a channel stop region 17 spaced from the emitter region and electrically connected to the collector electrode. The base region 4 includes a first region 4c between the emitter region and the channel stop region and a second region between the first region and the collector electrode, the first region having a higher minority-carrier-lifetime than the second region, whereby the first region provides a conductivity modulated conduction path between the emitter region and the channel stop region when the insulated gate bipolar transistor is reverse biased.

Abstract: The semiconductor device comprises a collector layer 14; a base layer 16 of a carbon-doped GaxIn1−xAsySb1−y layer having one surface connected to the collector layer 14; an emitter layer 18 connected the other surface of the base layer 16; a base contact layer 30 of a carbon-doped GaAsSb layer electrically connected to the base layer 16; and a base electrode 32 formed on the base contact layer 30. The semiconductor device of such structure can have a much reduced base resistance RB, whereby InP/GaInAsSb-based HBTs including InP/InGaAs-based HBTs can have higher maximum oscillation frequency fmax. Because of the carbon-doped semiconductor layer the semiconductor device can have higher reliability.

Abstract: A semiconductor device, such as a BiCMOS, includes a bipolar transistor having at least an emitter region. An emitter electrode is formed on the emitter region. Further, a wiring pattern is formed over the emitter region. A plurality of contact plugs are formed to electrically connect the emitter electrode with the wiring pattern. The contact plugs are partially embedded in the emitter electrode in order to prevent of reduction of the current amplification factor of the bipolar transistor.

Abstract: A process for fabricating semiconductor devices, comprises forming a surface film on the surface of a semiconductor substrate. The semiconductor substrate is doped with dopant through the surface film to form a dopant distribution layer. The doped surface film is removed, and then anneal is done to accomplish desired dopant profile of the box type.

Abstract: An improved BJT is described that maximizes both Bvceo and Ft/Fmax for optimum performance. Scattering centers are introduced in the collector region (80) of the BJT to improve Bvceo. The inclusion of the scattering centers allows the width of the collector region WCD (90) to be reduced leading to an improvement in Ft/Fmax.

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: A complementary bipolar transistor having a lateral npn bipolar transistor, a vertical and a lateral pnp bipolar transistor, an integrated injection logic, a diffusion capacitor, a polysilicon capacitor and polysilicon resistors are disclosed. The lateral pnp bipolar transistor has an emitter region and a collector region which includes high-density regions and low-density regions, and the emitter region is formed in an n type tub region. In the integrated injection logic circuit, collector regions are surrounded by a high-density p type region, and low-density p type regions are formed under the collector regions. The diffusion capacitor and the polysilicon capacitor are formed in one substrate. The diffusion regions except the regions formed by diffusing the impurities in the polysilicon resistors into the epitaxial layer are formed before forming the polysilicon resistors, and polysilicon electrodes are formed along with the polysilicon resistors.

Abstract: To provide a semiconductor device that has a positive ON-voltage temperature coefficient and a high switching speed at the current densities provided during actual operation. A (p) anode layer 1 is formed on one surface of an (n) base layer 3 having high resistance, and an (n) cathode layer 2 is formed on the other surface. The surface of the (p) anode layer 1 is coated with an insulating film having contact slots formed therein, and the anode electrode 5 is formed on the (p) anode layer 1 and is fixed to the (p) anode layer 1 at the locations of the contact slots 7. A cathode electrode 6 is formed on the (n) cathode layer 2. In addition, the planar pattern of the contact slots 7 is shaped like stripes. The area ratio S1/S2 is 5 or more and 30 or less, where area S1 constitutes the (p) anode layer 1 that is occupied by an insulating film 4 (the area of a non-secured portion), and area S2 represents the locations of the contact slots 7 (the area of the secured portion).

Abstract: An n− epitaxial layer serving as a collector region is formed on a p-type silicon substrate. A p diffusion layer serving as a base region is formed on the n− epitaxial layer. An n− diffusion layer and an n+ diffusion layer defining an emitter region are formed on the p diffusion layer. A p+ diffusion layer serving as a base contact region for attaining contact with the p diffusion layer is formed with a prescribed interval between the same and the emitter region. Thus obtained is a semiconductor device comprising a transistor suppressing dispersion of a current amplification factor.

Abstract: This invention includes a semiconductor substrate of one conductivity type having a semiconductor layer of an opposite conductivity type from an upper surface to a predetermined depth and first and second projections on the semiconductor layer of the opposite conductivity type, a first insulating film formed on an upper surface of the semiconductor substrate of one conductivity type from a portion except for the first and second projections to a predetermined level not reaching upper surfaces of the first and second projections, a semiconductor film of one conductivity type formed on at least the upper surface of the first projection, a first semiconductor film of the opposite conductivity type formed on at least the upper surface of the second projection, and a second semiconductor film of the opposite conductivity type formed in a predetermined position on an upper surface of the semiconductor film of one conductivity type. This structure allows an emitter to be formed without any alignment.

Abstract: The invention relates to semiconductor devices having a bipolar transistor to form an isolation area within a base electrode contact area to ensure stable contact of the base electrode. The bipolar transistor formed in the transistor area is in the form of an island and is rectangular when view from above. The isolation area is formed of a dielectric material around the transistor area, and the base area is formed around the emitter area which forms the central area of the transistor area. A contact groove is formed at the inner interface of the isolation groove which faces the outer surface of the transistor area, and a part of the base electrode is buried in the contact groove and faces at least one of the upper surface of the transistor area and an inner surface of the contact groove.

Abstract: In a semiconductor device having a diffusion-layer structure wherein high-concentration impurities are diffused into a low-impurity-concentration diffusion layer, two or more arrays of high-concentration diffusion layers are formed in each of diffusion layers constituting a collector region, an emitter region and a base region. Contacts are connected to their respective diffusion layers. A breakdown occurs on the diffusion layers, and heat generated therefrom is transmitted to the contacts.

Abstract: A semiconductor integrated circuit has a protective NMOS transistor having a drain and a source respectively electrically connected to a first interconnection (electrically connected to a base electrode of a bipolar transistor or a gate electrode of a MOS transistor) and ground and a gate electrode in a floating state, upon formation of the first interconnection. The first interconnection is formed by patterning using plasma etching and is connected to ground after the formation of the first interconnection.

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: Methods of forming bipolar junction transistors having preferred base electrode extensions include the steps of forming a base electrode of second conductivity type (e.g., P-type) on a face of a substrate. A conductive base electrode extension layer is then formed in contact with a sidewall of the base electrode. The base electrode extension layer may be doped or undoped. An electrically insulating base electrode spacer is then formed on the conductive base electrode extension layer, opposite the sidewall of the base electrode. The conductive base electrode extension layer is then etched to define a L-shaped base electrode extension, using the base electrode spacer as an etching mask. Dopants of second conductivity type are then diffused from the base electrode, through the base electrode extension and into the substrate to define an extrinsic base region therein.