Fermi Level Unpinning and Schottky Barrier Modification by Ti, Sc and V Incorporation at NiSi₂/Si Interface

A new method is proposed to modify the Schottky barrier height (SBH) for nickel silicide/Si contact. Chemical and electrical properties for NiSi₂/Si interface with titanium, scandium and vanadium incorporation are investigated by first-principles calculations. The metal/semiconductor interface states within the gap region are greatly decreased, which is related to the diminutions of junction leakage when Ti-cap is experimentally used in nickel silicide/Si contact process. It leads to an unpinning metal/semiconductor interface. The SBH obeys the Schottky-Mott theory. Compared to Ti substitution, the SBH for electrons is reduced for scandium and increases for vanadium.