Type-II localized interface states and Si surface preparation for Ni, Pt, Al/Si Schottky diodes

Abstract

Evidence for a new class of genuinely localized interface states for Ni, Pt, Al-Si Schottky diodes has been obtained from capacitance-voltage measurements. They are in electrical equilibrium with Si, and have short relaxation times (<10-6 s). They give an exponential contribution to the capacitance which is only weakly sensitive to the silicon surface preparation and exhibits a smooth variation with the nature of the metal. These features are consistent with the existence of a Si conduction band tail in the vicinity of the interface as predicted by Inkson.