Modeling and characterization for high-speed GaAlAs-GaAs n-p-n heterojunction bipolar transistors

A numerical one-dimensional model is employed to predict dc and switching characteristics for n-p-n type GaAlAs-GaAs transistors, including heteroemitter-homocollector and heteroemitter-heterocollector junction structure, where four kinds of doping profiles are considered. Also, Si and GaAs homojunction transistors are referred to for comparison. Switching performance is discussed for a single unit case, with and without a base resistance, and for a DCTL-type two-stage inverter case, including the delay time dependence on fanout.