A bipolar transistor includes a sub-collector doped with a first dopant type and situated in a semiconductor substrate, a device layer doped with the first dopant type situated over the sub-collector, and a shallow trench isolation (STI) situated in the device layer and bordering a collector of the bipolar transistor. The bipolar transistor further includes a Reduced Surface Layer (RESURF) region doped with a second dopant type opposite the first dopant type situated between the collector and the STI, wherein the RESURF region protects against breakdown of the bipolar transistor.

Device structures for a bipolar junction transistor. A layer is formed on a top surface of a substrate. A trench is formed in the layer and has a plurality of sidewalls with a width between an opposite pair of the sidewalls that varies with increasing distance from the top surface of the substrate. A collector pedestal of the bipolar junction transistor is formed in the trench.

Device structures and fabrication methods for a bipolar junction transistor. A first semiconductor layer is formed on a substrate containing a first terminal. An etch stop layer is formed on the first semiconductor layer, and a second semiconductor layer is formed on the etch stop layer. The second semiconductor layer is etched to define a second terminal at a location of an etch mask on the second semiconductor layer. A first material comprising the etch stop layer and a second material comprising the second semiconductor layer are selected such that the second material of the second semiconductor layer etches at a greater etch rate than the first material of the etch stop layer. The first semiconductor layer may be a base layer that is used to form an intrinsic base and an extrinsic base of the bipolar junction transistor.

Systems and methods are disclosed for integrating functional components of front-end modules for wireless radios. Front-end modules disclosed may be dual-band front-end modules for use in 802.11ac-compliant devices. In certain embodiments, integration of front-end module components on a single die is achieved by implementing a high-resistivity layer or substrate directly underneath, adjacent to, and/or supporting SiGe BiCMOS technology elements.

A method for forming a bipolar junction transistor includes forming a collector intrinsic region, an emitter intrinsic region and an intrinsic base region between the collector intrinsic region and the emitter intrinsic region. A collector extrinsic contact region is formed in direct contact with the collector intrinsic region; an emitter extrinsic contact region is formed on the emitter intrinsic region and a base extrinsic contact region is formed in direct contact with the intrinsic base region. Carbon is introduced into at least one of the collector extrinsic contact region, the emitter extrinsic contact region and the base extrinsic contact region to suppress diffusion of dopants into the junction region.

Device structures for a bipolar junction transistor and methods of fabricating a device structure for a bipolar junction transistor. A first semiconductor layer is formed on a substrate, and a second semiconductor layer is formed on the first semiconductor layer. The first semiconductor layer, the second semiconductor layer, and the substrate are etched to define first and second emitter fingers from the second semiconductor layer and trenches in the substrate that are laterally positioned between the first and second emitter fingers. The first semiconductor layer may function as a base layer in the device structure.

This disclosure relates to bipolar transistors, such as heterojunction bipolar transistors, having at a doping spike in the collector. The doping spike can be disposed relatively near an interface between the collector and the base. For instance, the doping spike can be disposed within half of the thickness of the collector from the interface between the collector and the base. Such bipolar transistors can be implemented, for example, in power amplifiers.

The present disclosure relates to semiconductor structures and, more particularly, to vertical heterojunction bipolar transistors and methods of manufacture. The structure includes: a sub-collector region; a collector region above the sub-collector region; an intrinsic base above the collector region; an emitter above the intrinsic base region; and an extrinsic base on the intrinsic base and adjacent to the emitter, wherein the collector region includes an undercut profile comprising lower inwardly tapered sidewalls and upper inwardly tapered sidewalls which extend to a narrow section between the sub-collector region and the base region.

A heterojunction bipolar transistor device includes a substrate, a metallic sub-collector layer, a collector layer, a base layer, an emitter layer, a base electrode, and a plurality of emitter strips. The metallic sub-collector layer is formed over the substrate. The collector layer is formed over the metallic sub-collector layer. The base layer is formed over the collector layer. The emitter layer is formed over the base layer. The base electrode is formed over the base layer and includes a plurality of base fingers. The plurality of emitter strips are formed over the emitter layer and are arranged alternately with the plurality of base fingers.

The present disclosure generally relates to semiconductor processing integration for a bipolar junction transistor (BJT). In an example, a semiconductor device includes a semiconductor substrate, an etch stop layer, a pedestal dielectric layer, a BJT, and a field effect transistor (FET). The semiconductor substrate includes a BJT region and a complementary FET (CFET) region. The etch stop layer is over the semiconductor substrate in the BJT region. The pedestal dielectric layer is over the etch stop layer in the BJT region. The BJT is on the semiconductor substrate in the BJT region. At least a first portion of the BJT is in an opening through the pedestal dielectric layer and the etch stop layer. At least a second portion of the BJT is further over the pedestal dielectric layer. The FET is on the semiconductor substrate in the CFET region.