Temperature dependence of Schottky barrier height on Si: Experimental evidence for Fermi energy pinning relative to either valence or conduction band

Abstract

We investigated the temperature dependence of Schottky barrier heights in epitaxial silicide/silicon diodes, using internal photoemission techniques. Temperature variation of the Fermi level position in the Si band gap shows that the Fermi level at the interface is pinnedeither relative to the Si conduction bandor to the Si valence band. The contribution of the semiconductor to the interface states is restricted to the semiconductor band nearest in energy. We then discuss the effect of the metal on the interface states and propose different models of Schottky barrier formation which may account for these results.