Structural, electronic and optical properties of AlN-based oxides on Si and GaN substrates

The properties of novel high-quality AlN-based oxides suitable for device applications are presented in this paper. The process steps employed in this investigation are similar to these of SiO/sub 2/, providing new technology for group III-nitride based electronic devices. The oxides were prepared by thermal oxidation of AlN films or direct deposition of ultra-pure aluminum in a O/sub 2/-N/sub 2/ ambient on Si or GaN substrates. The structure of the films depends on deposition conditions for oxidized AlN and on composition for the Al films deposited in the N/sub 2/-O/sub 2/ ambient. The dielectric constant was evaluated to be 12.74 while the effective charge density is about 10/sup 11/ cm/sup -2/ for fully oxidized AlN. The refractive index of the oxide was about 3.9 using infrared techniques. Our results indicate that the AlN-based oxides provide a wide choice of high-quality insulators for electronic and optoelectronic applications.