Heterojunction Zn-doped bipolar transistors were prepared by means of metal-organic chemical vapor deposition. The characteristics of heterojunction bipolar transistors with an undoped spacer layer and an n-type GaAs set-back layer (heterostructure-emitter) between base and emitter were investigated. The results showed that base dopant out-diffusion was effectively prevented in heterostructure-emitter bipolar transistors.

Y.F.Yang, C.C.Hsu, E.S.Yang: Semiconductor Science and Technology, 1995, 10[3], 339-43