Method of making unpinned oxide-compound semiconductor structures

Abstract

Unpinned epitaxial metal-oxide-compound semiconductor structures are disclosed and a method of fabricating such structures is described. Epitaxial layers of compound semiconductor are grown by MBE which result in the formation of a smooth surface having a stabilized reconstruction. An elemental semiconductor layer is deposited epitaxially in-situ with the compound semiconductor layer which unpins the surface Fermi level. A layer of insulator material is then deposited on the elemental semiconductor layer by PECVD. In one embodiment, the compound semiconductor is GaAs and the elemental semiconductor is Si. The insulator material is a layer of high quality SiO.sub.2. A metal gate is deposited on the SiO.sub.2 layer to form an MOS device. The epitaxial GaAs layer has a density of states which permits the interface Fermi level to be moved through the entire forbidden energy gap. In another embodiment, the SiO.sub.2 deposition completely consumes the interface Si layer so that the resulting MOS device comprises SiO.sub.2 directly overlying the GaAs layer.

Dependencies are inferred from the claim text.