Hydrogen passivation of shallow-acceptor impurities in<i>p</i>-type GaAs

Abstract

It is shown for the first time that hydrogen passivation of p-type GaAs produces electrical compensation of the shallow-acceptor impurity. This is demonstrated with capacitance-voltage and secondary-ion-mass spectrometry measurements on hydrogenated Zn-doped GaAs. In addition, it is shown that for comparable net dopant concentrations, passivation is far more extensive in p-type as compared to n-type GaAs; both metal-organic chemical-vapor-deposited (Zn and Se doped) and bulk GaAs (Zn and Si doped) were investigated. It is proposed that hydrogen passivation of Zn acceptors in GaAs involves interstitial diffusion of hydrogen to the vicinity of a zinc atom that is located at a gallium site. The hydrogen atom specifically bonds to an arsenic atom that is adjacent to the zinc. From the experimental results it is inferred that hydrogen passivation of shallow-acceptor impurities is a general physical phenomenon in semiconductors.