Analysis of the GaAs/GaAsBi Material System for Heterojunction Bipolar Transistors

This paper reports on the simulation of a double heterojunction bipolar transistor using the novel GaAs/GaAsBi material system. Published material parameters were used to simulate the device performance using an analytic drift-diffusion device model. DC and RF parameters were calculated as a function of emitter current density, base thickness and doping, and emitter stripe width and doping. Current gain is predicted to be between 10² and 10³ at a current density of >; 10⁵ A/cm² and a bismuth concentration of 1.5%-3%. RF performance was calculated to range from 10 to 30 GHz for fT and from 100 to 120 GHz for f_max at a current density of 105 A/cm², base thickness of 100-200 nm, and emitter stripe width of 0.1-1 μm.