High-Performance InGaP/GaAs pnp δ-Doped Heterojunction Bipolar Transistor

In this article, a novel InGaP/GaAs pnp δ-doped heterojunction bipolar transistor is first demonstrated. Though the valence band discontinuity at InGaP/GaAs heterojunction is relatively large, the addition of a δ-doped sheet between two spacer layers at the emitter-base junction effectively eliminates the potential spike and increases the barrier for electrons, simultaneously. Experimentally, a high current gain of 22 and an offset voltage of 100 mV are achieved. The offset voltage is much smaller than the reported InGaP/GaAs npn HBTs. The proposed device can be used for linear amplifiers and low power complementary integrated circuit applications.