Abstract: A semiconductor device includes: a first semiconductor layer made of an AlxGa1-xN (0?x<1); a second semiconductor layer provided on the first semiconductor layer and made of an undoped or first conductivity type AlyGa1-yN (0<y?1, x<y); an anode electrode and a cathode electrode which are connected to the second semiconductor layer; and a third semiconductor layer of second conductivity type provided between the anode electrode and the cathode electrode when viewed from a direction perpendicular to an upper surface of the second semiconductor layer. The third semiconductor layer is depleted when a predetermined magnitude or more of voltage is applied between the anode electrode and the cathode electrode.

Abstract: A bipolar junction transistor (BJT) and method for fabricating such. The transistor includes an emitter region, a collector region, and an intrinsic-base region. The intrinsic-base region is positioned between the emitter region and the collector region. Furthermore, the physical separation between the emitter region and the collector region is less than the sum of a base-emitter space-charge region width and a base-collector space-charge region width at the transistor's standby mode.

Abstract: A heterojunction bipolar transistor (HBT), an integrated circuit (IC) chip including at least one HBT and a method of forming the IC. The HBT includes an extrinsic base with one or more buried interstitial barrier layer. The extrinsic base may be heavily doped with boron and each buried interstitial barrier layer is doped with a dopant containing carbon, e.g., carbon or SiGe:C. The surface of the extrinsic base may be silicided.

Abstract: A switching device for heterojunction integrated circuits is disclosed. According to one aspect, the switching device is configured to protect a circuit from an electro-static discharge (ESD) event. The switching device includes a second base contact region that is configured to be electrically floating, a first base contact region and a collector contact region that are coupled to a first input terminal of the switching device, and an emitter contact region that is coupled to a second input terminal of the switching device. Due in part to capacitive coupling between the first base contact region and the second base contact region, the switching device exhibits a low transient trigger voltage and a fast response to ESD events. Further, the switching device exhibits a high DC trigger voltage (for example, greater than 20V), while maintaining relatively low leakage current during operation (for example, less than about 0.5 ?A at 20V DC.

Abstract: Disclosed are a transistor (e.g., bipolar junction transistor (BJT) or a heterojunction bipolar transistor (HBT)) and a method of forming the transistor with a narrow in-substrate collector region for reduced base-collector junction capacitance. The transistor has, within a substrate, a collector region positioned laterally adjacent to a trench isolation region. A relatively thin seed layer covers the trench isolation region and collector region. This seed layer has a monocrystalline center, which is aligned above and wider than the collector region (e.g., due to a solid phase epitaxy regrowth process), and a polycrystalline outer section. An intrinsic base layer is epitaxially deposited on the seed layer such that it similarly has a monocrystalline center section that is aligned above and wider than the collector region. An extrinsic base layer is the intrinsic base layer and has a monocrystalline extrinsic base-to-intrinsic base link-up region that is offset vertically from the collector region.

Abstract: A high-speed SiGe HBT is disclosed, which includes: a substrate; STIs formed in the substrate; a collector region formed beneath the substrate surface and located between the STIs; an epitaxial dielectric layer including two portions, one being located on the collector region, the other being located on one of the STIs; a base region formed both in a region between and on surfaces of the two portions of the epitaxial dielectric layer; an emitter dielectric layer including two portions, both portions being formed on the base region; an emitter region formed both in a region between and on surfaces of the two portions of the emitter dielectric layer; a contact hole formed on a surface of each of the base region, the emitter region and the collector region. A method of manufacturing high-speed SiGe HBT is also disclosed.

Abstract: A silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) device that includes a substrate; a buried oxide layer near a bottom of the substrate; a collector region above and in contact with the buried oxide layer; a field oxide region on each side of the collector region; a pseudo buried layer under each field oxide region and in contact with the collector region; and a through region under and in contact with the buried oxide layer. A method for manufacturing a SiGe HBT device is also disclosed. The SiGe HBT device can isolate noise from the bottom portion of the substrate and hence can improve the intrinsic noise performance of the device at high frequencies.

Abstract: Methods of fabricating semiconductor devices or structures include bonding a layer of semiconductor material to another material at a temperature, and subsequently changing the temperature of the layer of semiconductor material. The another material may be selected to exhibit a coefficient of thermal expansion such that, as the temperature of the layer of semiconductor material is changed, a controlled and/or selected lattice parameter is imparted to or retained in the layer of semiconductor material. In some embodiments, the layer of semiconductor material may comprise a III-V type semiconductor material, such as, for example, indium gallium nitride. Novel intermediate structures are formed during such methods. Engineered substrates include a layer of semiconductor material having an average lattice parameter at room temperature proximate an average lattice parameter of the layer of semiconductor material previously attained at an elevated temperature.

Abstract: A high-voltage metal-oxide-semiconductor (HVMOS) device may include a source, a drain, a gate positioned proximate to the source, a drift region disposed substantially between the drain and a region of the gate and the source, and a self shielding region disposed proximate to the drain. A corresponding method is also provided.

Abstract: A wafer comprising at least one emitter-up Heterojunction Bipolar Transistor (HBT) and at least one emitter-down HBT on a common InP based semiconductor wafer. Isolation and N-type implants into the device layers differentiate an emitter-down HBT from an emitter-up HBT. The method for preparing a device comprises forming identical layers for all HBTs and performing ion implantation to differentiate an emitter-down HBT from an emitter-up HBT.

Abstract: A combinationally doped semiconductor layer, a double heterojunction bipolar transistor (DHBT) including a combinationally doped semiconductor layer, and a method of making a combinationally doped semiconductor layer employ a combination of carbon and beryllium doping. The combinationally doped semiconductor layer includes a first sublayer of a semiconductor material doped substantially with beryllium and a second sublayer of the semiconductor material doped substantially with carbon. The DHBT includes a carbon-beryllium combinationally doped semiconductor layer as a base layer. The method of making a combinationally doped semiconductor layer includes growing a first sublayer of the semiconductor layer, the first sublayer being doped substantially with beryllium and growing a second sublayer of the semiconductor layer, the second sublayer being doped substantially with carbon.

Abstract: A method for fabricating an electronic device, comprising wafer bonding a first semiconductor material to a III-nitride semiconductor, at a temperature below 550° C., to form a device quality heterojunction between the first semiconductor material and the III-nitride semiconductor, wherein the first semiconductor material is different from the III-nitride semiconductor and is selected for superior properties, or preferred integration or fabrication characteristics in the injector region as compared to the III-nitride semiconductor.

Abstract: A highly sensitive and wide spectra-range mesa type photodetector having the impurity diffusion along the mesa-sidewall is provided. A mesa-type hetero-bipolar phototransistor or photodiode having a photo-absorption layer formed by a first semiconductor layer of a first conductivity type, an anode layer (or base layer) formed by a second semiconductor layer of a second conductivity type which has an opposite polarity with the first conductivity type, a wide band gap emitter or window layer formed by the third semiconductor layer on the anode layer, and the wide band gap buffer layer of the first conductivity type which has a relatively wide band gap semiconductor as compared with the second semiconductor layer on the substrate, which also serves as the cathode layer. And the first semiconductor layer, the second semiconductor layer and the wide band gap emitter or window layer is selectively etched to form the mesa structure.

Abstract: The invention concerns a heterojunction bipolar transistor comprising a support, and epitaxially grown from said support, at least: one collecting, respectively emitting, layer; at least one base layer; and at least one emitting, respectively collecting, layer. The collecting, respectively emitting, layer comprises: at least one first undercoat contacted with said base layer, substantially of similar composition as said emitting, respectively collecting, layer; and at least one second undercoat on the side opposite said base layer relative to said first undercoat.

Abstract: A horizontal heterojunction bipolar transistor (HBT) includes doped single crystalline Ge having a doping of the first conductivity type as the base having an energy bandgap of about 0.66 eV, and doped polysilicon having a doping of a second conductivity type as a wide-gap-emitter having an energy bandgap of about 1.12 eV. In one embodiment, doped polysilicon having a doping of the second conductivity type is employed as the collector. In other embodiments, a single crystalline Ge having a doping of the second conductivity type is employed as the collector. In such embodiments, because the base and the collector include the same semiconductor material, i.e., Ge, having the same lattice constant, there is no lattice mismatch issue between the collector and the base. In both embodiments, because the emitter is polycrystalline and the base is single crystalline, there is no lattice mismatch issue between the base and the emitter.

Abstract: A semiconductor device includes: a first semiconductor layer made of an AlxGa1?xN (0?×<1); a second semiconductor layer provided on the first semiconductor layer and made of an undoped or first conductivity type AlyGa1?yN (0<y?1, x<y); an anode electrode and a cathode electrode which are connected to the second semiconductor layer; and a third semiconductor layer of second conductivity type provided between the anode electrode and the cathode electrode when viewed from a direction perpendicular to an upper surface of the second semiconductor layer. The third semiconductor layer is depleted when a predetermined magnitude or more of voltage is applied between the anode electrode and the cathode electrode.

Abstract: A SiGe HBT formed on a silicon substrate is disclosed. An active area is isolated by field oxide regions; a collector region is formed in the active area and extends into the bottom of the field oxide regions; pseudo buried layers are formed at the bottom of the field oxide regions, wherein each pseudo buried layer is separated by a lateral distance from the active area and connected to a lateral extension part of the collector region; first deep hole contacts are formed on top of the pseudo buried layers in the field oxide regions to pick up collector electrodes; a plurality of second deep hole contacts with a floating structure, are formed in the field oxide region on top of a lateral extension part of the collector region, wherein N-type implantation regions are formed at the bottom of the second deep hole contacts.

Abstract: Methods and apparatuses for forming a device structure including a high-thermal-conductivity substrate are disclosed herein. A method forming such a device structure may comprise forming an active layer over a first substrate in a manner such that a frontside of the active layer faces the first substrate and a backside of the active layer faces away from the first substrate, forming a second substrate over the backside of the active layer, and removing the first substrate to expose the frontside of the active layer. Other embodiments are described and claimed.

Abstract: A heterojunction bipolar transistor (HBT) having an emitter, a base, and a collector, the base including a first semiconductor layer coupled to the collector, the first semiconductor layer having a first bandgap between a first conduction band and a first valence band and a second semiconductor layer coupled to the first semiconductor layer and having a second bandgap between a second conduction band and a second valence band, wherein the second valence band is higher than the first valence band and wherein the second semiconductor layer comprises a two dimensional hole gas and a third semiconductor layer coupled to the second semiconductor layer and having a third bandgap between a third conduction band and a third valence band, wherein the third valence band is lower than the second valence band and wherein the third semiconductor layer is coupled to the emitter.

Abstract: Embodiments relate to a method for forming a wiring in a semiconductor device, that may include laminating a conductive layer for wiring formation on a semiconductor substrate, forming a photoresist layer pattern on the conductive layer, performing primary dry etching for the conductive layer after employing the photoresist layer pattern as a mask, thereby forming a wiring pattern, partially removing the photoresist layer pattern through secondary dry etching, thereby forming a passivation layer on a surface of the wiring pattern, performing tertiary dry etching for the wiring pattern and a diffusion barrier after employing the photoresist layer pattern as a mask, thereby forming a metal wiring, and removing the photoresist layer pattern.

Abstract: One or more embodiments relate to a semiconductor device, comprising: a substrate; and a radio frequency coupler including a first coupling element and a second coupling element spacedly disposed from the first coupling element, the first coupling element including at least one through-substrate via disposed in the substrate, the second coupling element including at least one through-substrate via disposed in the substrate.

Abstract: A thin-film crystal wafer having a pn junction includes a first crystal layer of p GaAs, a second crystal layer of n InxAlyGa1?x?yP, the first and second crystal layers being lattice-matched layers that form a heterojunction, and a control layer of a thin-film of InxAlyGa1?x?yP differing in composition from the n InxAlyGa1?x?yP of the second crystal layer is formed at the interface of the heterojunction. The control layer enables the energy discontinuity at the interface of the InxAlyGa1?x?yP/GaAs heterojunction to be set within a relatively broad range of values and thus enables the current amplification factor and the offset voltage to be matched to specification values by varying the energy band gap at the heterojunction.

Abstract: A process for manufacturing an array of bipolar transistors, wherein deep field insulation regions of dielectric material are formed in a semiconductor body, thereby defining a plurality of active areas, insulated from each other and a plurality of bipolar transistors are formed in each active area. In particular, in each active area, a first conduction region is formed at a distance from the surface of the semiconductor body; a control region is formed on the first conduction region; and, in each control region, at least two second conduction regions and at least one control contact region are formed. The control contact region is interposed between the second conduction regions and at least two surface field insulation regions are thermally grown in each active area between the control contact region and the second conduction regions.

Abstract: The present invention refers to a method for preparing a non-self-aligned heterojunction bipolar transistor comprising: preparing a patterned emitter metal on an emitter epi layer of a HBT epi structure on a substrate; preparing an emitter epitaxy below the emitter metal; applying a resist layer on the top surface covering the emitter metal and emitter epitaxy, and the base layer; applying lithography leaving the emitter epitaxy and the emitter metal covered by the resist vertically with a width pD and leaving a pattern according to the mask in the resist; depositing base metal on the entire surface; and removing the remaining resist and the base metal covering the resist defining a base metal, the base metal being spaced from the emitter epitaxy and the emitter metal by a distance xD from 0.05 ?m to 0.7 ?m. The present invention refers to a non-self-aligned heterojunction bipolar transistor as prepared by this method.

Abstract: The present invention provides a layout for a self-aligned semiconductor device, comprising an emitter mesa structure having an emitter electrode, and a base region that is comprised of a base electrode, with the base electrode deposited along crystal planes of the emitter mesa structure that undercut when the emitter mesa structure is etched, while avoiding depositing of the base electrode along crystal planes of the emitter mesa structure that do not undercut when the emitter mesa structure is etched. This allows the emitter electrode and the base electrode to self-align along the crystal planes that the emitter mesa structure undercuts when etched, and be isolated along the crystal planes that the emitter mesa structure does not undercut when etched. The present invention further provides dual interconnects mechanism and for connecting external circuitry to various semiconductor layers.

Abstract: An object of the present invention is to provide a semiconductor resistive element having excellent linearity. A semiconductor device according to the present invention includes a HBT which is formed on a GaAs substrate and includes a group III-V compound semiconductor, and a semiconductor resistive element made of at least one layer included in a semiconductor epitaxial layer included in the HBT, and the semiconductor resistive element includes helium impurities.

Abstract: Semiconductor device structures for use with bipolar junction transistors and methods of fabricating such semiconductor device structures. The semiconductor device structure includes a semiconductor body having a top surface and sidewalls extending from the top surface to an insulating layer, a first region including a first semiconductor material with a first conductivity type, and a second region including a second semiconductor material with a second conductivity type. The first and second regions each extend across the top surface and the sidewalls of the semiconductor body. The device structure further includes a junction defined between the first and second regions and extending across the top surface and the sidewalls of the semiconductor body.

Abstract: A method for forming a germanium-enriched region in a heterojunction bipolar transistor and a heterojunction bipolar transistor comprising a germanium-enriched region. A base having a silicon-germanium portion is formed over a collector. Thermal oxidation of the base causes a germanium-enriched region to form on a surface of the silicon-germanium portion subjected to the thermal oxidation. An emitter is formed overlying the germanium-enriched portion region. The germanium-enriched region imparts advantageous operating properties to the heterojunction bipolar transistor, including improved high-frequency/high-speed operation.

Abstract: The present invention relates to a microelectronic device having a bipolar epitaxial structure that provides at least one bipolar transistor element formed over at least one field effect transistor (FET) epitaxial structure that provides at least one FET element. The epitaxial structures are separated with at least one separation layer. Additional embodiments of the present invention may use different epitaxial layers, epitaxial sub-layers, metallization layers, isolation layers, layer materials, doping materials, isolation materials, implant materials, or any combination thereof.

Abstract: An embodiment relates to a memory cell comprising a programmable resistance memory element electrically coupled to a heterojunction bipolar transistor.

Abstract: Provided are an optoelectronic (OE) transmitter integrated circuit (IC) and method of fabricating the same using a selective growth process. In the OE transmitter IC, a driving circuit, which includes a double heterojunction bipolar transistor (DHBT) and amplifies received electric signals to drive an electroabsorption (EA) modulator, and the EA modulator with a multi-quantum well (MQW) absorption layer are integrated as a single chip on a semi-insulating substrate. The MQW absorption layer of the EA modulator and an MQW insertion layer of the DHBT are formed to different thicknesses from each other using a selective MOCVD growth process.

Abstract: This invention pertains to heterojunction bipolar transistors containing a semiconductor substrate, a buffer layer of an antimony-based material deposited on the substrate, a sub-collector layer of an antimony-based material deposited on the buffer layer, a collector layer of an antimony-based material deposited on the sub-collector layer, a base layer of an antimony-based material deposited on the collector layer, an emitter layer of an antimony-based material deposited on the base layer, and a cap layer of an antimony-based material deposited on the emitter layer.

Abstract: The invention provides a method for fabricating a heterojunction bipolar transistor with a base connecting region (23), which is formed self-aligned to a base region (7) without applying photolithographic techniques. Further, a collector connecting region (31) and an emitter region (29) are formed simultaneously and self-aligned to the base connecting region (23) without applying photolithographic techniques.

Abstract: Semiconductor device structures for use with bipolar junction transistors and methods of fabricating such semiconductor device structures. The semiconductor device structure comprises a semiconductor body having a top surface and sidewalls extending from the top surface to an insulating layer, a first region including a first semiconductor material with a first conductivity type, and a second region including a second semiconductor material with a second conductivity type. The first and second regions each extend across the top surface and the sidewalls of the semiconductor body. The device structure further comprises a junction defined between the first and second regions and extending across the top surface and the sidewalls of the semiconductor body.

Abstract: A heterojunction bipolar transistor: The transistor may a collector layer, a base layer and an emitter layer. The transistor may include a dielectric material being disposed over the base layer. The base layer may be a SiGe base layer.

Abstract: The present invention refers to a method for preparing a non-self-aligned heterojunction bipolar transistor comprising: preparing a patterned emitter metal on an emitter epi layer of a HBT epi structure on a substrate; preparing an emitter epitaxy below the emitter metal; applying a resist layer on the top surface covering the emitter metal and emitter epitaxy, and the base layer; applying lithography leaving the emitter epitaxy and the emitter metal covered by the resist vertically with a width pD and leaving a pattern according to the mask in the resist; removing the remaining resist and the base metal covering the resist defining a base metal, the base metal being spaced from the emitter epitaxy and the emitter metal by a distance xD. The present invention refers to a non-self-aligned heterojunction bipolar transistor as prepared by this method.

Abstract: A method for producing a compound semiconductor wafer used for production of HBT by vapor growth of a sub-collector layer, a collector layer, a base layer and an emitter layer in this turn on a compound semiconductor substrate using MOCVD method wherein the base layer is grown as a p-type compound semiconductor thin film layer containing at least one of Ga, Al and In as a Group III element and As as a Group V element under such growth conditions that the growth rate gives a growth determined by a Group V gas flow rate-feed.

Abstract: The HBT-based transient suppression device contains a collector layer of a first conduction type, a base layer of a second conduction type, an emitter layer of the first conduction type, stacked in this order sequentially on a top side of a heavily doped substrate of the first conduction type. The doping concentration of the base layer is higher than that of the emitter and collector layers, and that the thickness of the collector layer is less than 300 nm, so that the BVCEO breakdown voltage is reduced below 5V Additionally, the thickness of the base layer is larger than the sum of the thickness of a section of the emitter-base depletion region extending into the base layer and the thickness of a section of the base-collector depletion region extending into the base layer, so that the base layer is not operated in a punch-through condition.

Abstract: Bipolar junction transistors (BJTs) and single or double heterojunction bipolar transistors with low parasitics, and methods for making the same is presented. A transistor is fabricated such that the collector region underneath a base contact area is deactivated. This results in a drastic reduction of the base-collector parasitic capacitance, Cbc. An embodiment of the present invention provides a transistor architecture for which the base contact area can be decoupled from the collector and hence allows for dramatic reduction in the parasitics of transistors.

Abstract: On a substrate of a GaN FET, an undoped AlN layer, a GaN delta doped layer, an undoped GaN layer, and an undoped Al0.2Ga0.8N layer are formed in sequence. Arranged on the undoped Al0.2Ga0.8N layer are a Ti/Al/Pt/Au source ohmic electrode, a Pt/Au gate Schottky electrode, and a Ti/Al/Pt/Au drain ohmic electrode. Parallel conduction and gate leak are reduced or eliminated by the GaN delta doped layer.

Abstract: The invention relates to a method of manufacturing a bipolar transistor on a semiconductor substrate (11) which is provided with a first, a second and a third layer (1,2,3) of a first, second and third semiconductor material respectively, all of a first conductivity type. A first portion of the second layer (2) is transformed into a buried isolation region (15) comprising a first electrically insulating material. A first semiconductor region (6) of the first conductivity type, comprising, for example, a collector region, is formed from a second portion of the second layer (2) adjoining the buried isolation region (15) and a portion of the first layer (1) adjoining the second portion of the second layer (2). Then a base region (7) is formed on the buried isolation region (15) and on the first semiconductor region (6) by transforming the third layer (3) into a second conductivity type, which is opposite to the first conductivity type.

Abstract: A transistor epitaxial wafer having: a substrate; an n-type collector layer, a p-type base layer and an n-type emitter layer formed on the substrate in this order; and an n-type InGaAs non-alloy layer having an n-type InGaAs nonuniform composition layer formed on the n-type emitter layer and having an nonuniform indium (In) composition, and an n-type InGaAs uniform composition layer formed on the n-type InGaAs nonuniform composition layer and having a uniform indium (In) composition. The n-type InGaAs nonuniform composition layer has a first layer doped with Si and having a low indium (In) composition, and a second layer formed on the first layer, doped with an n-type dopant except Si, and having an indium (In) composition higher than the first layer.

Abstract: An oxide layer is formed on material defining and surrounding an emitter window. The technique comprises depositing a non-conformal oxide layer on the surrounding material and in the emitter window, whereby the thickness of at least a portion of the oxide layer in the emitter window is smaller than the thickness of the oxide layer on the surrounding material outside the emitter window; and removing at least a portion of the oxide layer in the emitter window so as to reveal at least a portion of the bottom of the emitter window whilst permitting at least a portion of the oxide layer to remain on the surrounding material. The technique can be used in the manufacture of a self-aligned epitaxial base BJT (bipolar junction transistor) or SiGe HBT (hetero junction bipolar transistor).

Abstract: A hot electron transistor includes a collector layer, a base layer, an emitter layer, a collector barrier layer formed between the collector layer and the base layer, and an emitter barrier layer formed between the base layer and the emitter layer. An energy barrier between the emitter barrier layer and the emitter layer does not substantially exist and the height of an energy barrier of the collector barrier layer is lower than the height of an energy barrier of the emitter barrier layer.

Abstract: The present invention refers to a method for preparing a non-self-aligned heterojunction bipolar transistor comprising: preparing a patterned emitter metal on an emitter epi layer of a HBT epi structure on a substrate; preparing an emitter epitaxy below the emitter metal; applying a resist layer on the top surface covering the emitter metal and emitter epitaxy, and the base layer; applying lithography leaving the emitter epitaxy and the emitter metal covered by the resist vertically with a width pD and leaving a pattern according to the mask in the resist; depositing base metal on the entire surface; and removing the remaining resist and the base metal covering the resist defining a base metal, the base metal being spaced from the emitter epitaxy and the emitter metal by a distance xD from 0.05 ?m to 0.7 ?m. The present invention refers to a non-self-aligned heterojunction bipolar transistor as prepared by this method.

Abstract: A bipolar transistor structure includes an intrinsic base layer formed over a collector layer, an emitter formed over the intrinsic base layer, and an extrinsic base layer formed over the intrinsic layer and adjacent the emitter. A ring shaped collector implant structure is formed within an upper portion of the collector layer, wherein the ring shaped collector implant structure is disposed so as to be aligned beneath a perimeter portion of the emitter.

Abstract: A heterojunction bipolar transistor and a method of making a heterojunction bipolar transistor. The heterojunction bipolar transistor includes: a regrown emitter region; an intrinsic base region forming a junction with the regrown emitter region; and an extrinsic base region separated from the regrown emitter region. The thickness of the extrinsic base region is greater than the thickness of the intrinsic base region.

Abstract: A bipolar junction transistor is provided. A p-type well region surrounds an n-type emitter and connects with the bottom of the emitter to serve as a base. A p-type base pick-up region connects with the base and surrounds the emitter. An n-type deep well, connected to the bottom of the base and the bottom of the n-type well, is used as a collector. The n-type well surrounds the base and connects with the n-type deep well. An n-type collector pick-up region connects with the n-type well and surrounds the base. An isolation structure is disposed between the emitter and the base and between a portion of the base and a portion of the n-type well. A buffer region is disposed under a portion of the isolation structure. Furthermore, the buffer region together with a portion of the isolation structure isolates the p-type base from the n-type well.

Abstract: In the method for manufacturing a heterojunction bipolar transistor, a collector contact layer, a collector layer, a base layer, a base protection layer, an emitter layer, an emitter contact layer, and a WSi layer are sequentially formed on a substrate. A resist pattern is then formed on the WSi layer, and the WSi layer is patterned by using the resist pattern as a mask. Thereafter, the emitter contact layer and the emitter layer are sequentially removed by ICP (Inductively Coupled Plasma) dry etching by using the resist pattern as a mask.

Abstract: In a nitride semiconductor device according to one embodiment of the invention, a p-type gallium nitride (GaN) layer electrically connected to a source electrode and extending and projecting to a drain electrode side with respect to a gate electrode is formed on an undoped or n-type aluminum gallium nitride (AlGaN) layer serving as a barrier layer.