High Quality GaN Grown by Reactive Sputtering

Gallium nitride films were grown by reactive rf magnetron sputtering on sapphire substrates. Crystalline (1120) GaN films were obtained on (0112) sapphire at substratestemperatures between 640-680 °C. High N₂ partial pressures are required to crystalize the GaN films. Nitrogen incorporation and crystal quality of GaN films are examined as a function of substrate temperature and nitrogen partial pressure. Band gaps of 3.4 eV, and photoluminescence peaks as narrow as 11 meV are reported for sputtered GaN films.