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 semiconductor device includes a single semiconductor substrate on which an IGBT region including an IGBT element and an FWD region including a FWD element are formed. In the semiconductor device, a cathode layer is formed with a carrier injection layer, which is electrically connected to a second electrode and has a PN junction with a field stop layer. When a first carrier in the FWD element passes through the field stop layer on the carrier injection layer and flows into the cathode layer in a situation where a forward-biased current is cut off from a state in which the forward-biased current is flowing through the FWD element, a second carrier is injected from the second electrode into a drift layer through the carrier injection layer.

This disclosure relates to methods of forming bipolar transistors, such as heterojunction bipolar transistors. The methods may include forming a sub-collector over a substrate, forming a first portion of a collector over the sub-collector and doping a second portion of the collector to form a doping spike. The method may further include forming a third portion of the collector over the doping spike and forming a base of the bipolar transistor over the third portion of the collector.

Embodiments provide a method for manufacturing a bipolar junction transistor, comprising: providing a semiconductor substrate comprising a buried layer of a first conductive type; doping the semiconductor substrate in a collector implant region, to obtain a collector implant of the first conductive type extending parallel to a surface of the semiconductor substrate and from the surface of the semiconductor substrate to the buried layer; providing a base layer of a second conductive type on the surface of the semiconductor substrate, the base layer covering the collector implant; providing a sacrificial emitter structure on the base layer, wherein a projection of an area of the sacrificial emitter structure is enclosed by an area of the collector implant; and partially counter doping the collector implant through an area of the base layer surrounding an area of the base layer that is covered by the sacrificial emitter structure.

Methods according to the present disclosure include: providing a substrate including: a first semiconductor region, a second semiconductor region, and a trench isolation (TI) laterally between the first and second semiconductor regions; forming an epitaxial layer on at least the first semiconductor region of the substrate, wherein the epitaxial layer includes a first semiconductor base material positioned above the first semiconductor region of the substrate; forming an insulator region on at least the first semiconductor base material, the trench isolation (TI), and the second semiconductor region; forming a first opening in the insulator over the second semiconductor region; and growing a second semiconductor base material in the first opening, wherein a height of the second semiconductor base material above the substrate is greater than a height of the first semiconductor base material above the substrate.

Device structures and fabrication methods for a heterojunction bipolar transistor. A collector of the device structure has a top surface and a sidewall that is inclined relative to the top surface. The device structure further includes an emitter, an intrinsic base that has a first thickness, and an extrinsic base coupled with the intrinsic base. The extrinsic base has a lateral arrangement relative to the intrinsic base and relative to the emitter. The intrinsic base has a vertical arrangement between the emitter and the top surface of the collector. The sidewall of the collector extends laterally to undercut the extrinsic base. The extrinsic base has a second thickness that is greater than a first thickness of the intrinsic base.

One aspect of this disclosure is a power amplifier module that includes a power amplifier die, a first bonding pad on a conductive trace, and a second bonding pad on a conductive trace. The die includes an on-die passive device and a power amplifier. The first bonding pad is electrically connected to the on-die passive device by a first wire bond. The second bonding pad is in a conductive path between the first bonding pad and a radio frequency output of the power amplifier module. The second bonding pad includes a nickel layer having a thickness that is less than 0.5 um, a palladium layer over the nickel layer, and a gold layer over the palladium layer and bonded to a second wire bond that is electrically connected to an output of the power amplifier. Other embodiments of the module are provided along with related methods and components thereof.

Disclosed is a SiGe, HBT, and method of manufacturing the same, comprising: an n-doped buried collector; a p-doped SiGe base layer, within a layer stack, the layer stack being over and in direct contact with the collector; an n-doped monocrystalline silicon emitter; an epitaxial silicon base contact layer over a second area of the layer stack; a polycrystalline silicon emitter contact layer; an oxide layer over a third area of the layer stack between the first and second areas, wherein the oxide layer and the n-doped monocrystalline silicon emitter are within a window, having sidewalls, in the epitaxial silicon layer; dielectric spacers on the sidewalls of the window and over the oxide layer, and providing electrical isolation between the epitaxial silicon layer and the polycrystalline silicon layer; the epitaxial silicon layer extending beneath the dielectric spacers on the sidewalls of the window.

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 and fabrication methods for a heterojunction bipolar transistor. A collector of the device structure has a top surface and a sidewall that is inclined relative to the top surface. The device structure further includes an emitter, an intrinsic base that has a first thickness, and an extrinsic base coupled with the intrinsic base. The extrinsic base has a lateral arrangement relative to the intrinsic base and relative to the emitter. The intrinsic base has a vertical arrangement between the emitter and the top surface of the collector. The sidewall of the collector extends laterally to undercut the extrinsic base. The extrinsic base has a second thickness that is greater than a first thickness of the intrinsic base.