Abstract: An analytical model is used to predict the effects of surface recombination current on the gain and transit time of GaInP/GaAs heterojunction bipolar transistors (HBTs). The present analysis shows that consideration of the recombination current gives current gain values that are comparable to those of the experimental results. The dependence of current gain on temperature, base doping and emitter area are also analyzed, and the variation in collector current with emitter-base voltage, temperature and doping is considered.

Key words: GaInP/GaAs HBT, current gain, transit time, recombination current, surface recombination, ideality factor