Heterojunction and interface space charge effects on interstitial Be diffusion during molecular beam epitaxy (MBE) growth

Abstract

High level Be incorporation and diffusion during MBE growth of GaAs(P+)/GaAs(N) homo and GaAs(P+)/AlGaAs(N) heterojunctions have been shown to be strongly affected by the interfacial heterojunction and space charge electric field for the first time. The onset of fast Be interstitial diffusion is determined mainly by the MBE growth temperature, and partially influenced by the III–V flux ratio. The experimental result indicates that the Be diffusion species at the MBE growth surface is indeed positively charged as predicted by the hole tunneling, surface implantation model, hence the Be diffusion species slow down in the presence of higher opposing space charge electric field.