Method for passivating a compound semiconductor surface and device

Abstract

A method for passivating the surface of a compound semiconductor comprises annealing the substrate to form an anion rich surface layer containing cationic and anionic oxides and stripping the oxides to leave only a very thin anionic layer on the surface. The substrate is then subjected to an H.sub.2 plasma cleaning to remove chemisorbed oxygen. An N.sub.2 plasma cleaning is then performed to form an anionic nitride layer that is free of any cationic nitride. A layer of insulating material, such as, a native or other oxide, or a nitride, is deposited. The resulting structure has a very low interface state density such that the Fermi level may be swept through the entire band gap.