Abstract: Disclosed is a method of forming a heterojunction bipolar transistor (HBT), comprising depositing a first stack comprising an polysilicon layer (16) and a sacrificial layer (18) on a mono-crystalline silicon substrate surface (10); patterning the first stack to form a trench (22) extending to the substrate; depositing a silicon layer (24) over the resultant structure; depositing a silicon-germanium-carbon layer (26) over the resultant structure; selectively removing the silicon-germanium-carbon layer (26) from the sidewalls of the trench (22); depositing a boron-doped silicon-germanium-carbon layer (28) over the resultant structure; depositing a further silicon-germanium-carbon layer (30) over the resultant structure; depositing a boron-doped further silicon layer (32) over the resultant structure; forming dielectric spacers (34) on the sidewalls of the trench (22); filling the trench (22) with an emitter material (36); exposing polysilicon regions (16) outside the side walls of the trench by selectively remo

Abstract: According to an example embodiment, a heterostructure bipolar transistor, HBT, includes shallow trench isolation, STI, structures around a buried collector drift region in contact with a buried collector. A gate stack including a gate oxide and a gate is deposited and etched to define a base window over the buried collector drift region and overlapping the STI structures. The etching process is continued to selectively etch the buried collector drift region between the STI structures to form a base well. SiGeC may be selectively deposited to form epitaxial silicon-germanium in the base well in contact with the buried collector drift region and poly silicon-germanium on the side walls of the base well and base window. Spacers are then formed as well as an emitter.

Abstract: The present invention discloses an electronic device comprising a generator for generating a stream (125) of charge carriers. The generator comprises a bipolar transistor (100) having an emitter region (120), a collector region (160) and a base region (140) oriented between the emitter region (120) and the collector region (160), and a controller for controlling exposure of the bipolar transistor (100) to a voltage in excess of its open base breakdown voltage (BVCEO) such that the emitter region (120) generates the stream (125) of charge carriers from a first area being smaller than the emitter region surface area. The electronic device may further comprise a material (410) arranged to receive the stream of charge carriers for triggering a change in a property of said material, the emitter region (120) being arranged between the base region (140) and the material (410).