A semiconductor structure includes following components. A first substrate has a first surface and a second surface opposite to each other. An HBT device is located on the first substrate and includes a collector, a base, and an emitter. A first interconnect structure is electrically connected to the base, located on the first surface, and extends to the second surface. A second interconnect structure is electrically connected to the emitter, located on the first surface, and extends to the second surface. A third interconnect structure is located on the second surface and electrically connected to the collector. An MOS transistor device is located on a second substrate and includes a gate, a first source and drain region, and a second source and drain region. Interconnect structures on the second substrate electrically connect the base to the first source and drain region and electrically connect the emitter to the gate.

A bipolar transistor includes a collector layer, a base layer, and an emitter layer that are formed in this order on a compound semiconductor substrate. The emitter layer is disposed inside an edge of the base layer in plan view. A base electrode is disposed on partial regions of the emitter layer and the base layer so as to extend from an inside of the emitter layer to an outside of the base layer in plan view. An insulating film is disposed between the base electrode and a portion of the base layer, with the portion not overlapping the emitter layer. An alloy layer extends from the base electrode through the emitter layer in a thickness direction and reaches the base layer. The alloy layer contains at least one element constituting the base electrode and elements constituting the emitter layer and the base layer.

A bipolar transistor includes a substrate, a sub-collector layer, a collector layer, a base layer, an emitter layer, a passivation layer, and a collector electrode. The sub-collector layer is formed over the substrate. The collector layer is formed over the sub-collector layer. The base layer is formed over the collector layer. The emitter layer is formed over the base layer. The passivation layer is formed over the substrate and covering a sidewall of the collector layer. The collector electrode is connected to the sub-collector layer through an opening in the passivation layer. The opening exposes at least a portion of the sub-collector layer.

A bipolar transistor has a subcollector layer and a stack of collector, base, and emitter layers on the subcollector layer. On the subcollector layer are collector electrodes. On the base layer are base electrodes. The collector layer includes multiple doped layers with graded impurity concentrations, higher on the subcollector layer side and lower on the base layer side. Of these doped layers, the one having the highest impurity concentration is in contact with the subcollector layer and has a sheet resistance less than or equal to about nine times that of the subcollector layer.

A collector layer, a base layer, an emitter layer, and an emitter mesa layer are placed above a substrate in this order. A base electrode and an emitter electrode are further placed above the substrate. The emitter mesa layer has a long shape in a first direction in plan view. The base electrode includes a base electrode pad portion spaced from the emitter mesa layer in the first direction. An emitter wiring line and a base wiring line are placed on the emitter electrode and the base electrode, respectively. The emitter wiring line is connected to the emitter electrode via an emitter contact hole. In the first direction, the spacing between the edges of the emitter mesa layer and the emitter contact hole on the side of the base wiring line is smaller than that between the emitter mesa layer and the base wiring line.

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.

A heterojunction bipolar transistor includes an emitter layer on a base layer on a collector layer on an upper sub-collector layer over a bottom sub-collector layer, a first dielectric film over the bottom sub-collector layer, the base layer and the emitter layer, a base electrode on the first dielectric film, electrically connected to the base layer through at least one first via hole in the first dielectric film, a second dielectric film on the first dielectric film and the base electrode, and a conductive layer on the second dielectric film, with conductive layer electrically connected to base electrode through a second via hole disposed in the second dielectric film, first dielectric film between the base electrode and first sidewall of a stack including the base layer and the collector layer, and second via hole laterally separated from the base layer.

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 above the sub-collector region; an intrinsic base region composed of intrinsic base material located above the collector region; an emitter located above and separated from the intrinsic base material; and a raised extrinsic base having a stepped configuration and separated from and self-aligned to the emitter.

A semiconductor device is provided with a first layer having a first layer conductive contact and being doped at a first concentration of a first dopant type. The first dopant type being a P type dopant. A second layer is on top the first layer and being doped at a second concentration of the first dopant type. The second concentration being less than the first concentration. A third layer is on top of the second layer and having a third layer conductive contact and being doped with a second dopant type, the second dopant type being an N type dopant. A fourth layer is on top of the third layer and having a fourth layer conductive contact and being doped with the first dopant type, wherein at least one of the first and second layers is a boron arsenide (BAs) layer.

Flexible transistors and electronic circuits incorporating the transistors are provided. The flexible transistors promote heat dissipation from the active regions of the transistors while preserving their mechanical flexibility and high-frequency performance. The transistor designs utilize thru-substrate vias (TSVs) beneath the active regions of thin-film type transistors on thin flexible substrates. To promote rapid heat dissipation, the TSVs are coated with a material having a high thermal conductivity that transfers heat from the active region of the transistor to a large-area ground.