ALGAAS GAAS HETEROJUNCTION BIPOLAR-TRANSISTORS WITH C-DOPED BASE GROWN BY AP-MOVPE

C-doped GaAs layers were grown by the atmospheric pressure metalorganic vapor phase epitaxy (AP-MOVPE) method using TMGa and TMAs at low temperature and low V/III ratio. Carbon concentrations up to 7 X 10(19) cm-3 were obtained, and their mobility was higher than for Zn-doped GaAs. Using this C-doped GaAs as the base layer, AlGaAs/GaAs HBTs were fabricated, and current gain up to 50 was demonstrated for the sample with a base layer of 700 angstrom in thickness and 4 X 10(19) cm-3 in concentration. The uniformity across the wafer and the reproducibility of the current gains were considered to be good enough for the use of this epitaxial layers as HBT ICs.