InGaP/InGaAs/GaAs DHBT structural materials grown by GSMBE

Abstract

Heterojunction bipolar transistor (HBT) is of great interest for the application to microwave power and analog circuits. As known, decreasing bandgap energy of the base layer in HBT can result in a smaller turn-on voltage. Using InGaAs as a base material in GaAs HBT is a possible approach to achieve the aim. In this work, a novel InGaP/InGaAs/GaAs double heterojunction bipolar transistor (DHBT) structure with an InGaAs base was designed and grown by gas source molecular beam epitaxy (GSMBE). High-quality InGaAs/GaAs hetero epi-layers and a good doping figure were obtained through optimizing the layer structure and the growth condition. The DHBT devices of a 120 μm × 120 μm emitter area were fabricated by normal process and the good DC performance was obtained. A breakdown voltage of 10 V and an offset voltage of just 0.4 V were achieved. These results indicate that the InGaP/InGaAs/GaAs DHBT is suitable for low power-dissipation and high power applications.