HIGH-CURRENT-GAIN GA-0.51IN-0.49P GAAS HETEROJUNCTION BIPOLAR-TRANSISTOR GROWN BY GAS-SOURCE MOLECULAR-BEAM EPITAXY/

A Ga0.51In0.49P/GaAs heterojunction bipolar transistor (HBT) grown on a (100) substrate by gas-source molecular beam epitaxy (GSMBE) was fab ricated. A common-emitter dc current gain exceeding 1580 (differential gain > 2100) and an offset voltage as small as 120 mV were achieved. The results demonstrate that high current gain and small offset voltag e could be maintained without the need of grading the emitter/base jun ction in the Ga0.51In0.49P/GaAs system because of its larger valence-b and discontinuity than conduction-band discontinuity. To our knowledge , the electrical current gain achieved was the highest value ever repo rted in Ga0.51In0.49P/GaAs system HBT's.