SCHOTTKY BARRIERS AND THE REACTIVITY OF THE INTERFACE

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