Method of manufacturing heterojunction bipolar transistor and heterojunction bipolar transistor

Abstract

Disclosed is a method of forming a heterojunction bipolar transistor (HBT), comprising depositing a first stack comprising an polysilicon layer () and a sacrificial layer () on a mono-crystalline silicon substrate surface (); patterning the first stack to form a trench () extending to the substrate; depositing a silicon layer () over the resultant structure; depositing a silicon-germanium-carbon layer () over the resultant structure; selectively removing the silicon-germanium-carbon layer () from the sidewalls of the trench (); depositing a boron-doped silicon-germanium-carbon layer () over the resultant structure; depositing a further silicon-germanium-carbon layer () over the resultant structure; depositing a boron-doped further silicon layer () over the resultant structure; forming dielectric spacers () on the sidewalls of the trench (); filling the trench () with an emitter material (); exposing polysilicon regions () outside the side walls of the trench by selectively removing the sacrificial layer () of the first stack; implanting boron impurities into the exposed polysilicon regions () to define base implants; and exposing the resultant structure to a thermal budget for annealing the boron impurities. A HBT formed by this method is also disclosed.