Pinning-controlled metal/semiconductor interfaces

Abstract

We propose a new systematical method to control Schottky barrier heights of metal/semiconductor interfaces by controlling the density of interface electronic states and the number of charges in the states. The density of interface states is controlled by changing the density of surface electronic states, which is controlled by hydrogenation. We apply an establishing hydrogen termination technique for the hydrogenation using a chemical solution, pH controlled buffered HF or hot water. The density of interface charges is changeable by controlling a metal work ftinction. When the density of interface states is completely hydrogenated, the barrier height is determined simply by the difference between a work function of a metal ç4,, and an electron affinity of a semiconductor . In such an interface with zero density of interface states, an Ohmic contact with a zero barrier height is formed when we select a metal with q5,,, < ,. We have already demonstrated controlling Schottky and Ohmic properties by changing the hydrogenation on silicon carbide (0001) surfaces.