Tunneling anomaly in disordered metal silicide-silicon junctions

Tunneling measurements on Ti-, Cr-, and Al-Schottky diodes are performed after transient annealing to form an interfacial silicide. A large zero-bias resistance anomaly is observed for Ti and Cr with a square-root law in the temperature dependence. The observation is interpreted in terms of electron-electron correlation in a disordered metal layer at the silicide-silicon interface. For aluminum which does not form a silicide, the tunneling anomaly is not observed.