Surface passivation of GaAs with ultrathin Si3N4/Si interface control layer formed by MBE and in situ ECR plasma nitridation

GaAs surfaces were successfully passivated by utilizing an ultrathin Si3N4/Si interface control layer (ICL) formed by molecular beam epitaxy (MBE) and in situ electron-cyclotron-resonance (ECR) plasma-assisted nitridation. Detailed X-ray photoelectron spectroscopy (XPS) analysis showed that optimization of the ECR plasma process led to the realization of well-defined Si3N4/Si double-layer structure without change in chemical status of GaAs surface. As compared with the clean MBE surface, surface Fermi level pinning became weaker and the band-edge photoluminescence (PL) intensity became larger after passivation.