CRYSTALLINE ORIENTATION CONTROL FOR ALUMINUM NITRIDE FILMS PREPARED BY ION-BEAM-ASSISTED TECHNOLOGY

Aluminum nitride films were prepared by evaporation of aluminum and simultaneous bombardment of nitrogen ions in the low-energy region 200-1000 eV (IVD method) on substrates of fused silica and on Si (100), (111) wafers. The ion incident angle was changed from 0-degrees to 45-degrees from the normal to the substrate surface, and the relation between the direction of ion incidence, ion beam energies, and crystalline orientation of AlN films was studied. X-ray diffraction patterns indicated that each film had a hexagonal structure and the direction of the (002) axis was parallel to the ion beam direction. Every film showed the same tendency irrespective of the substrate used. In addition, the dielectric constants of the AlN films were measured by means of an impedance analyzer and ellipsometry. The relation between the direction of crystalline orientation and the dielectric constant was also studied.