Device structures for a bipolar junction transistor and methods of fabricating a device structure for a bipolar junction transistor. A base layer comprised of a first semiconductor material is formed. An emitter layer comprised of a second semiconductor material is formed on the base layer. The emitter layer is patterned to form an emitter finger having a length and a width that changes along the length of the emitter finger.

Device structures and fabrication methods for a device structure. One or more trench isolation regions are formed in a substrate to surround a device region. A base layer is formed on the device region. First and second emitter fingers are formed on the base layer. A portion of the device region extending from the first emitter finger to the second emitter finger is free of dielectric material.

The methods of manufacture of GeSiSn heterojunction bipolar transistors, which include light emitting transistors and transistor lasers and photo-transistors and their related structures are described herein. Other embodiments are also disclosed herein.

A lateral bipolar junction transistor including a base region on a dielectric substrate layer. The base region includes a layered stack of alternating material layers of a first lattice dimension semiconductor material and a second lattice dimension semiconductor material. The first lattice dimension semiconductor material is different from the second lattice dimension semiconductor material to provide a strained base region. A collector region is present on the dielectric substrate layer in contact with a first side of the base region. An emitter region is present on the dielectric substrate in contact with a second side of the base region that is opposite the first side of the base region.

In one embodiment, a semiconductor device comprises one or more defense layers, the one or more defense layers each characterized by at least two lattice constants that are mismatched, wherein a mismatch in the lattice constants causes a destabilizing force that comprises at least one of a tensile force or a compressive force; and a plurality of other layers, wherein at least a sufficient part of the destabilizing force is restrained for the one or more defense layers to remain intact unless reduction in thickness of at least a section of one or more of the plurality of other layers, causes at least some of the destabilizing force that was restrained to no longer be restrained, and consequently at least part of at least one of the one or more defense layers to break.

Strain is used to enhance the properties of p- and n-materials so as to improve the performance of III-N electronic and optoelectronic devices. In one example, transistor devices include a channel aligned along uniaxially strained or relaxed directions of the III-nitride material in the channel. Strain is introduced using buffer layers or source and drain regions of different composition.

Certain aspects of the present disclosure generally relate to a semiconductor device with a heterojunction bipolar transistor (HBT) integrated with a gate-all-around (GAA) transistor. One example semiconductor device generally includes a first substrate, a second substrate adjacent to the first substrate, a GAA transistor disposed above the first substrate, and a HBT disposed above the second substrate. Other aspects of the present disclosure generally relate to a method for fabricating a semiconductor device. An exemplary fabrication method generally comprises forming a GAA transistor disposed above a first substrate and forming a HBT disposed above a second substrate, wherein the second substrate is adjacent to the first substrate.

An integrated circuit includes one or more bipolar transistors, each including a first dielectric layer located over a semiconductor layer having a first conductivity type, the dielectric layer including an opening. A second dielectric layer is located between the first dielectric layer and the semiconductor layer. The second dielectric layer defines a first recess between the first dielectric layer and the semiconductor substrate at a first side of the opening, and a second recess between the first dielectric layer and the semiconductor substrate at a second opposite side of the opening. A first doped region of the semiconductor layer is located under the opening, the first doped region having a different second conductivity type and a first width. A second doped region of the semiconductor layer is also under the opening, the second doped region having the second conductivity type and underlying the first recess and the second recess.

The invention provides a structure of an emitter layer and a base layer that reduces the influence of a conduction band energy barrier generated at an interface between the emitter layer and the base layer on power amplifier characteristics for a GaAs HBT using InGaAs grown by pseudomorphic growth in the base layer. In the first invention, InGaP having a CuPt-type ordering is used in the emitter layer. In the second invention, a p-type impurity concentration of an InGaAs base layer grown by pseudomorphic growth is less in an emitter layer side portion than in a collector layer side portion.

The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes: a first semiconductor layer including a device region; a second semiconductor layer under the first semiconductor layer; a layer of conductive material between the first semiconductor layer and the second semiconductor layer; at least one contact extending to and contacting the layer of conductive material; and a device in the device region above the layer of conductive material.