InGaP/GaAsSb/GaAs DHBTs with low turn-on voltage and high current gain

An InGaP/GaAsSb/GaAs double heterojunction bipolar transistor (DHBT) is presented. It features the use of a fully strained pseudomorphic GaAsSb (Sb composition: 10.4%) as the base layer and an InGaP layer as the emitter, which both eliminates the misfit dislocations and increases the valence band discontinuity at the InGaP/GaAsSb interface. A current gain of 200 has been obtained from the InGaP/GaAsSb/GaAs DHBT, which is the highest value obtained from GaAsSb base GaAs-based HBTs. The turn-on voltage of the device is typically 0.914 V for the 10.4% Sb composition, which is 0.176 V lower than that of traditional InGaP/GaAs HBT. The results show that GaAsSb is a suitable base material for reducing the turn-on voltage of GaAs HBTs.