Si-GaP-Si heterojunction bipolar transistor (HBT) on Si substrate

摘要

A heterojunction bipolar transistor (HBT) is provided having a silicon substrate in which a conventional junction base is formed. A coherently strained layer of semiconductor material having a wider band gap than silicon, such as gallium phosphide, is formed over the base to form a first portion of an emitter multilayer. A second portion of the emitter multilayer comprises silicon which can be epitaxially grown on the coherently strained layer. A thin heteropotential barrier is thus formed at the base-emitter junction which preferentially allows electrons to move from emitter to base while significantly reducing hole current from base to emitter, thereby improving emitter injection efficiency and current gain.