Simulation study of InP/GaAsSb double heterojunction bipolar transistors

Device modeling using a two dimensional, drift-diffusion approach utilizing a commercial numerical device simulator has been used to investigate the operation and performance of InP/GaAsSb heterojunction bipolar transistors (HBTs). GaAsSb lattice matched to InP has an energy bandgap (0.72 eV) that is similar to that of InGaAs (0.75 eV) so that Sb-based HBTs have been proposed as a replacement for InGaAs-based HBTs. In particular, the conduction band lineup is more favorable at the base-collector, which makes the GaAsSb-based HBTs especially attractive for double heterojunction bipolar transistors (DHBTs) where higher breakdown voltages are desired. In this work, the results of device modeling will be compared initially with recent experimental reports to validate the modeling approach. Subsequently, the design and operation of the devices will be examined to investigate the factors controlling device performance in order to facilitate improvements in device design.