On the chemistry of passivated oxide–InP interfaces
Abstract
Passivating native oxide films (≊150 Å) have been prepared by anodic oxidation of InP. X-ray photoelectron spectroscopy (XPS) chemical depth profiles reveal a double layer structure with indium-rich oxides at the surface and phosphorous-rich In(PO3)3 glass-like oxides at the interface. High quality metal–insulator–semiconductor (MIS) structures are obtained after removing the semiconducting indium-rich outer oxide layer. The passivating properties of the interfacial In(PO3)3 oxide are discussed on the basis of chemical bonding configurations in the native oxide. It is suggested that In(PO3)3 has better intrinsic passivating properties than InPO4.