InN films deposited by rf reactive sputtering in pure nitrogen gas

Abstract

We have investigated the effect of deposition conditions on the crystal structure and optical properties of InN films deposited by reactive sputtering in pure nitrogen gas. InN films have been deposited onto glass, (0 0 0 1) sapphire and (1 1 1) Si substrates by rf reactive puttering of pure In target. The nitrogen gas pressure, substrate temperature and applied rf power were varied in the range of 0.5–1.3 Pa, RT∼600°C and 20–55 W, respectively. All deposited films had a wurtzite structure with strong 〈0 0 0 1〉 preferred orientation. In the case of the glass substrate, the full-width at half-maximum of InN 0 0 0 2 peak became large with increasing applied rf power and/or nitrogen gas pressure. The angular dispersion of the c -axis of films deposited onto sapphire increases with increasing substrate temperature. This behavior was similar to that of the films on glass substrates. The angular dispersion of the c -axis of films deposited on (1 1 1) Si at temperatures between 200° and 450°C was smaller than those films grown on the others. This may suggest the existence of some interactions between the growing InN film and (1 1 1) Si substrate.