Stages of formation and thermal stability of a gold-n-GaN interface

The interface between a thin Au film deposited on an atomically clean GaN surface has been investigated by means of synchrotron radiation scanning photoelectron microscopy. The first stages of the interface formation at room temperature and the evolution of the interface after stepwise annealing up to 870 °C have been studied. Our results reveal the temperature dependence of the Schottky barrier heights, caused by structural rearrangements below 500 °C, and by the formation of an Au gallium alloy above 500 °C. The effect of the reaction-induced heterogeneity of the interface on the local Schottky barriers is examined.