Surface barrier height in metal-SiC structures of 6H, 4H and 3C polytypes

We have studied metal-silicon carbide barrier height for various structures. Material of both n- and p-type conductivity 3C, 6H and 4H varieties have been used with Mo or Au Schottky barriers. In some cases, we observe a dependence of the barrier height on the uncompensated impurity concentration which cannot be explained in terms of the simple image force barrier lowering. It demands to take into account the total charge balance at the metal-semiconductor interface. The analysis of these data, together with other data on the surface barrier height, gives useful information for the development of high temperature devices.