CARBON-DOPED BASE GAAS-ALGAAS HBTS GROWN BY MOMBE AND MOCVD REGROWTH

We demonstrate for the first time high-quality GaAs-AlGaAs HBT's in which the carbon-doped base layers (p = 10 19− 1020cm-3, 400–800 Å thick) and Sn-doped collector and subcollectors layers are grown by MOMBE and a subsequent regrowth using MOCVD is used to provide the n+ AlGaAs emitter and GaAs/InGaAs contact layers. A current gain of Z0 was obtained for a base doping of 1019cm-3 (800 Å thick) in a 90-μm-diameter device, with ideality factors of 1.0 and 1.4 for the base–collector and emitter-base junctions, respectively, demonstrating the excellent regrowth-interface quality. For a base doping of 1020cm-3 (400 Å thick), the current gain decreased to 8. © 1990 IEEE