A heterojunction bipolar transistor includes a collector layer, a base layer, and an emitter layer that are stacked on a substrate. The collector layer includes a graded semiconductor layer in which an electron affinity increases from a side closer to the base layer toward a side farther from the base layer. An electron affinity of the base layer at an interface closer to the collector layer is equal to an electron affinity of the graded semiconductor layer at an interface closer to the base layer.

The present application teaches, among other innovations, power semiconductor devices in which breakdown initiation regions, on BOTH sides of a die, are located inside the emitter/collector regions, but laterally spaced away from insulated trenches which surround the emitter/collector regions. Preferably this is part of a symmetrically-bidirectional power device of the “B-TRAN” type. In one advantageous group of embodiments (but not all), the breakdown initiation regions are defined by dopant introduction through the bottom of trench portions which lie within the emitter/collector region. In one group of embodiments (but not all), these can advantageously be separated trench portions which are not continuous with the trench(es) surrounding the emitter/collector region(s).

A semiconductor device and fabrication method are described for manufacturing a heterojunction bipolar transistor by forming a silicon collector region in a substrate which includes a lower collector layer, a dopant diffusion barrier layer, and an upper collector layer, where the formation of the dopant diffusion barrier layer reduces diffusion of dopants from the lower collector layer into the upper collector layer during one or more subsequent manufacturing steps which are used to form a trench isolation region in the substrate along with a heterogeneous base region and a silicon emitter region.

Device structures and fabrication methods for a bipolar junction transistor. The device structure includes a substrate and a trench isolation region in the substrate. The trench isolation region surrounds an active region of the substrate. The device structure further includes a collector in the active region of the substrate, a base layer having a first section positioned on the active region and a second section oriented at an angle relative to the first section, an emitter positioned on the first section of the base layer, and an extrinsic base layer positioned over the trench isolation region and adjacent to the emitter. The second section of the base layer is laterally positioned between the extrinsic base layer and the emitter.

A heterojunction bipolar transistor includes: a substrate; a base mesa disposed on the substrate, wherein the base mesa includes a collector layer and a base layer disposed on the collector layer, and wherein in a top view, the base layer includes a first edge and a second edge opposite to the first edge; an emitter layer disposed on the base layer; a base electrode disposed on the substrate and connected to the base layer; a dielectric layer disposed on the base electrode, wherein a first via hole is formed in the dielectric layer at the first edge of the base layer, and a second via hole is formed in the dielectric layer at the second edge of the base layer; and a conductive feature disposed on the dielectric layer, wherein the conductive feature is connected to the base electrode through the first via hole and the second via hole.

Aspects of the disclosure provide a bipolar transistor structure with a sub-collector on a substrate, a first collector region on a first portion of the sub-collector, a trench isolation (TI) on a second portion of the sub-collector and adjacent the first collector region, and a second collector region on a third portion of the sub-collector and adjacent the TI. A base on first collector region and a portion of the TI. An emitter is on a first portion of the base above the first collector region. The base includes a second portion horizontally displaced from the emitter in a first horizontal direction, and horizontally displaced from the second collector region in a second horizontal direction orthogonal to the first horizontal direction.

A semiconductor device includes a semiconductor substrate, an emitter region, a base region and multiple accumulation areas, and an upper accumulation area in the multiple accumulation areas is in direct contact with a gate trench section and a dummy trench section, in an arrangement direction that is orthogonal to a depth direction and an extending direction, a lower accumulation area furthest from the upper surface of the semiconductor substrate in the multiple accumulation areas has: a gate vicinity area closer to the gate trench section than the dummy trench section in the arrangement direction; and a dummy vicinity area closer to the dummy trench section than the gate trench section in the arrangement direction, and having a doping concentration of the first conductivity type lower than that of the gate vicinity area.

Solder bumps are placed in direct contact with the silicon substrate of an amplifier integrated circuit having a flip chip configuration. A plurality of amplifier transistor arrays generate waste heat that promotes thermal run away of the amplifier if not directed out of the integrated circuit. The waste heat flows through the thermally conductive silicon substrate and out the solder bump to a heat-sinking plane of an interposer connected to the amplifier integrated circuit via the solder bumps.

A semiconductor device (300) comprising: a doped semiconductor substrate (302); an epitaxial layer (304), disposed on top of the substrate, the epitaxial layer having a lower concentration of dopant than the substrate; a switching region disposed on top of the epitaxial layer; and a contact diffusion (350) disposed on top of the epitaxial layer, the contact diffusion having a higher concentration of dopant than the epitaxial layer; wherein the epitaxial layer forms a barrier between the contact diffusion and the substrate.

A semiconductor device includes a bipolar junction transistor having a collector, a base, and an emitter. The collector includes a current collection region, a constriction region laterally adjacent to the current collection region, and a contact region laterally adjacent to the constriction region, located opposite from the current collection region. The current collection region, the constriction region laterally, and the contact region all have the same conductivity type. The base includes a current transmission region contacting the current collection region and a constricting well laterally adjacent to, and contacting, the current transmission region and contacting the constriction region. The current transmission region and the constricting well have an opposite conductivity type than the current collection region, the constriction region laterally, and the contact region.