SCHOTTKY BARRIERS AND THE REACTIVITY OF THE INTERFACE

Schottky's model for the barrier height of a metal-semiconductor inter face predicts a value of 1.1 eV for Ga on p-type Si. Previous investig ations of such Schottky diodes have shown that this barrier height is actually very small. Our results on hydrogen-passivated Si show an int ermediate barrier height that depends strongly on the properties of th e passivated surface. We explain this discrepancy as a case of a mixed -phase interface, where Ga forms a high Schottky barrier to the passiv ated Si surface and a low barrier to residual defects of the passivate d surface.