AlN epitaxial growth on atomically flat initially nitrided a-A1203 wafer

The (1702) cu-Al,O, surface and the initial nitriding AlN layer are investigated using tbe atomic-force microscope. The initial nitriding method is to convert the (1702) (Y-Al,O, surface to a nanometer-thick AlN single-crystal buffer layer. The epitaxial AlN film is deposited by metalorganic chemical vapor deposition with and without the initial nitriding. Atomic step structure is found to be formed after the H, annealing. The atomic step structure is maintained during the initial nitriding time up to 5 min. Smooth AlN epitaxial films have been successfully deposited on the 2 inch diameter (1702) a-Al,O, wafer without any inverse-twin throughout the wafer by keeping the atomic step structure of the initial nitriding buffer layer