Interfacial Oxide Layer in Au-Si Schottky Barriers

Abstract

This paper describes a method of obtaining experimental evidence on the existence of an interfacial layer in Si Schottky barriers. It is shown that capacitance-voltage and photoresponse measurements on metal-Si Schottky barriers can be utilized to investigate the properties of a metal-Si interface. By applying this method to Au-Si Schottky barriers, it becomes evident that the interfacial layer in Au-Si system is a thin SiO₂ film with a thickness of about 10Å. This method is applicable to metal-SiO₂-Si structures with an oxide thickness less than 20Å and Si donor concentrations between 1×10¹⁵ and 5×10¹⁶/cm³.
Brief discussions are given on the donor concentration dependence of the barrier height and the current transport mechanism of Au-Si Schottky barriers.