The effect of 900°C furnace annealing on transistors with in situ phosphorus-doped polysilicon emitters has been investigated. For devices with chemically grown interfacial oxides, annealing is essential to give acceptable emitter resistance and emitter Gummel numbers. For devices lacking an intentionally grown interfacial oxide, annealing is necessary to reduce the emitter resistance to a tolerable level, but it simultaneously lowers the emitter Gummel number.