Liquid phase oxidation for InGaP/GaAs HBT passivation

Abstract

Native oxide films grown near room temperature by liquid phase oxidation (LPO) on p+-GaAs, n-InGaAs and n-InGaP are investigated. Their applications to heterojunction bipolar transistors (HBTs) are also demonstrated and characterized. With the LPO as surface passivation, the dc current gain β of the HBT devices increases sevenfold in low collector current regimes, and it also shows wider collector regimes from 8.3 × 10−11 A to 0.1 A. In addition, a larger breakdown voltage and lower surface recombination current can be obtained. This provides the possibility of promising implementations in low-power electronics and communication applications. Comparisons between devices with LPO passivation and those with sulfur treatment on the InGaP/GaAs HBTs are also discussed.