Epitaxial Growth of AlN Film with an Initial-Nitriding Layer on α-Al₂O₃ Substrate

An epitaxial film of AlN with a flat surface and good crystallinity was grown on an α-Al 2 O 3 substrate by a new MOCVD. An initial-nitriding layer of the α-Al 2 O 3 surface was employed as a buffer layer to reduce a lattice mismatch between the AlN film and the α-Al 2 O 3 substrate. The initial-nitriding layer was formed by chemical conversion of the α-Al 2 O 3 surface in NH 3 gas at 1200°C.