Abstract: Device structures and fabrication methods for heterojunction bipolar transistors. Trench isolation regions are positioned in a semiconductor substrate to define active regions. A base layer includes first sections that are respectively positioned over the active regions and second sections that are respectively positioned over the trench isolation regions. Emitter fingers are respectively positioned on the first sections of the base layer. The first sections of the base layer include single-crystal semiconductor material, and the second sections of the base layer include polycrystalline semiconductor material. The second sections of the base layer are spaced in a vertical direction from the trench isolation regions to define a first cavity that extends about a perimeter of the base layer and second cavities that are connected to the first cavity.

Abstract: Device structures and fabrication methods for heterojunction bipolar transistors. Trench isolation regions are positioned in a semiconductor substrate to define active regions. A base layer includes first sections that are respectively positioned over the active regions and second sections that are respectively positioned over the trench isolation regions. Emitter fingers are respectively positioned on the first sections of the base layer. The first sections of the base layer include single-crystal semiconductor material, and the second sections of the base layer include polycrystalline semiconductor material. The second sections of the base layer are spaced in a vertical direction from the trench isolation regions to define a first cavity that extends about a perimeter of the base layer and second cavities that are connected to the first cavity.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to a device with a marker layer and methods of manufacture. The device includes: a collector region; an intrinsic base region above the collector region; an emitter region comprising emitter material and a marker layer vertically between the intrinsic base region and the emitter material; and an extrinsic base region in electrical contact with the intrinsic base region.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes: a sub-collector region in a substrate; a collector region above the sub-collector region, the collector region composed of semiconductor material; an intrinsic base region composed of intrinsic base material surrounded by the semiconductor material above the collector region; and an emitter region above the intrinsic base region.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes a collector region composed of semiconductor material; at least one marker layer over the collector region; a layer of doped semiconductor material which forms an extrinsic base and which is located above the at least one marker layer; a cavity formed in the layer of doped semiconductor material and extending at least to the at least one marker layer; an epitaxial intrinsic base layer of doped material located within the cavity; and an emitter material over the epitaxial intrinsic base layer and within an opening formed by sidewall spacer structures.

Abstract: A device structure for a bipolar junction transistor includes a base layer made of a semiconductor material. An emitter is disposed on a first portion of the base layer. A dopant-containing layer is disposed on a second portion of the base layer. A hardmask is disposed on the base layer. The hardmask includes a window aligned with the second portion of the base layer. Deposits of the dopant-containing layer are limited to exposed surfaces of: the first portion that is disposed on a top surface of the base layer inside of the window.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to a heterojunction bipolar transistor and methods of manufacture. The structure includes: a sub-collector region; a collector region in electrical connection to the sub-collector region; an emitter located adjacent to the collector region and comprising emitter material, recessed sidewalls on the emitter material and an extension region extending at an upper portion of the emitter material above the recessed sidewalls; and an extrinsic base separated from the emitter by the recessed sidewalls.

Abstract: Embodiments of the disclosure provide a transistor structure and methods to form the same. The transistor structure may include an active semiconductor region with a channel region between a first source/drain (S/D) region and a second S/D region. A polysilicon gate structure is above the channel region of the active semiconductor region. An overlying gate is positioned on the polysilicon gate structure. A horizontal width of the overlying gate is greater than a horizontal width of the polysilicon gate structure. The transistor structure includes a gate contact to the overlying gate.

Abstract: A junction field effect transistor (JFET) structure includes a doped polysilicon gate over a channel region of a semiconductor layer. The doped polysilicon gate has a first doping type. A raised epitaxial source is on the source region of the semiconductor layer and adjacent a first sidewall of the doped polysilicon gate, and has a second doping type opposite the first doping type. A raised epitaxial drain is on the drain region of the semiconductor layer and adjacent a second sidewall of the doped polysilicon gate, and has the second doping type. A doped semiconductor region is within the channel region of the semiconductor layer and extending from the source region to the drain region, and a non-conductive portion of the semiconductor layer is within the channel region to separate the doped semiconductor region from the doped polysilicon gate.

Abstract: Structures for a heterojunction bipolar transistor and methods of forming a structure for a heterojunction bipolar transistor. A collector layer includes an inclined side surface, and a dielectric layer is positioned in a lateral direction adjacent to the inclined side surface of the collector layer. An intrinsic base is disposed over the collector layer, and an emitter is disposed over the intrinsic base. An airgap is positioned between the dielectric layer and the inclined side surface of the collector layer in the lateral direction, and an extrinsic base is positioned in the lateral direction adjacent to the intrinsic base. The extrinsic base is positioned over the airgap.

Abstract: Structures for a heterojunction bipolar transistor and methods of forming a structure for a heterojunction bipolar transistor. A first heterojunction bipolar transistor includes a first emitter, a first collector, and a first base layer having a portion positioned between the first emitter and the first collector. A second heterojunction bipolar transistor includes a second emitter, a second collector, and a second base layer having a portion positioned between the second emitter and the second collector. The first and second base layers each comprise silicon-germanium, the first base layer includes a first germanium profile, and the second base layer includes a second germanium profile that is identical to the first germanium profile.

Abstract: Structures for transistor-based sensors and related fabrication methods. A layer stack is formed that includes a semiconductor layer and a cavity. A transistor is formed that has a gate electrode over the layer stack, and an interconnect structure is formed over the layer stack and the transistor. First and second openings are formed that extend through the metallization levels of the interconnect structure and the semiconductor layer to the cavity. The first opening defines a fluid inlet coupled to the cavity, and the second opening defines a fluid outlet coupled to the cavity.

Abstract: Device structures and fabrication methods for a bipolar junction transistor. A trench isolation region surrounds an active region that includes a collector. A base layer includes a first section and a second section that are located over the active region. An emitter is positioned on the first section of the base layer, and an extrinsic base layer is positioned on the second section of the base layer. The extrinsic base layer has a side surface adjacent to the emitter. The side surface of the extrinsic base layer is inclined relative to a top surface of the base layer in a direction away from the emitter.

Abstract: Structures for a heterojunction bipolar transistor and methods of forming a structure for a heterojunction bipolar transistor. A first heterojunction bipolar transistor includes a first emitter, a first collector, and a first base layer having a portion positioned between the first emitter and the first collector. A second heterojunction bipolar transistor includes a second emitter, a second collector, and a second base layer having a portion positioned between the second emitter and the second collector. The first and second base layers each comprise silicon-germanium, the first base layer includes a first germanium profile, and the second base layer includes a second germanium profile that is identical to the first germanium profile.

Abstract: Embodiments of the disclosure provide a transistor structure and methods to form the same. The transistor structure may include an active semiconductor region with a channel region between a first source/drain (S/D) region and a second S/D region. A polysilicon gate structure is above the channel region of the active semiconductor region. An overlying gate is positioned on the polysilicon gate structure. A horizontal width of the overlying gate is greater than a horizontal width of the polysilicon gate structure. The transistor structure includes a gate contact to the overlying gate.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to a heterojunction bipolar transistor and methods of manufacture. The structure includes: a sub-collector region; a collector region in electrical connection to the sub-collector region; an emitter located adjacent to the collector region and comprising emitter material, recessed sidewalls on the emitter material and an extension region extending at an upper portion of the emitter material above the recessed sidewalls; and an extrinsic base separated from the emitter by the recessed sidewalls.

Abstract: Structures for a heterojunction bipolar transistor and methods of forming a structure for a heterojunction bipolar transistor. A collector layer includes an inclined side surface, and a dielectric layer is positioned in a lateral direction adjacent to the inclined side surface of the collector layer. An intrinsic base is disposed over the collector layer, and an emitter is disposed over the intrinsic base. An airgap is positioned between the dielectric layer and the inclined side surface of the collector layer in the lateral direction, and an extrinsic base is positioned in the lateral direction adjacent to the intrinsic base. The extrinsic base is positioned over the airgap.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes: a sub-collector region in a substrate; a collector region above the sub-collector region, the collector region composed of semiconductor material; an intrinsic base region composed of intrinsic base material surrounded by the semiconductor material above the collector region; and an emitter region above the intrinsic base region.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to a device with a marker layer and methods of manufacture. The device includes: a collector region; an intrinsic base region above the collector region; an emitter region comprising emitter material and a marker layer vertically between the intrinsic base region and the emitter material; and an extrinsic base region in electrical contact with the intrinsic base region.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to virtual bulk in semiconductor on insulator technology and methods of manufacture. The structure includes a heterojunction bipolar transistor formed on a semiconductor on insulator (SOI) wafer with a doped sub-collector material in a buried insulator region under a semiconductor substrate of the SOI wafer.