Bipolar transistor.

摘要

A homojunction bipolar transistor having a superlattice base region (16) comprising alternate layers (18, 20) of extrinsic and intrinsic layers, with extrinsic layers (18) being of the opposite conductivity of the emitter (22) and collector layers (12, 14) of the transistor. The alternate extrinsic and intrinsic layers (18, 20) have substantially different doping levels providing abrupt transitions in the valence and conduction bands between layers. The abrupt transitions result in the energy band gap in the base region (16) being effectively reduced with respect to the band gap in the emitter region (22).