Electrical characteristics of metal/AlN/n-type 6H-SiC(0001) heterostructures

Metal/AlN/n-type 6H-SiC(0001) heterostructures have been prepared by growing wurtzite AlN layers on vicinal 6H-SiC(0001) using gas-source molecular beam epitaxy. High-resolution transmission electron microscopy results show that the interface between the AlN layer and the Si-terminated 6H-SiC substrate is microstructurally abrupt, but contains defects originating at step sites on the 6H-SiC surface. The interface is found to have a low density of trapped charges of 1 × 10¹¹ cm^-2 at room temperature without any postgrowth treatment. This value is comparable to those reported for thermally grown and deposited oxides on n-type 6H-SiC(0001), and indicates the formation of a high quality interface.