CRYSTAL ORIENTATION AND PIEZOELECTRICITY OF AIN THIN-FILMS PREPARED ON POLYCRYSTALLINE SUBSTRATES

Highly c-axis oriented AIN thin films were prepared on the polycrystalline substrates of MoSi2, A1(2)O(3) and SiC by rf magnetron sputtering. Crystal orientation of the thin films was not influenced by the difference in the polycrystalline substrate materials. Crystal structure of the thin him was hexagonal and its texture was consisted of many columnar grains. It was thought that the thin films were c-axis oriented because the interaction between the thin films and the substrate surfaces was small and the growth of (100) and (110) planes of AIN was fast. The orientation of the thin films deposited on the polycrystalline substrates was worse than that of thin films deposited on single crystal substrates, however, the thin films showed appreciable piezoelectricity.