A collector-up AlGaAs/GaAs heterojunction bipolar transistor fabricated using three-stage MOCVD

A new collector-up AlGaAs/GaAs heterojunction bipolar transistor (HBT) is reported. This structure is designed to minimize parasitic capacitance and to eliminate trenches for making contacts. The emitter, external base, and intrinsic base and collector have been grown in three stages using metalorganic chemical vapor deposition (MOCVD). The current gain of this collector-up HBT (C-up HBT) with a 5*14- mu m/sup 2/ collector is 15.<>