Substrate temperature dependence of GaN film deposited on sapphire substrate by high-density convergent plasma sputtering device

Abstract

Substrate temperature dependence of GaN films deposited on a sapphire substrate was studied by the high-density convergent plasma sputtering device (CPSD). The crystal structure, surface morphology, and film stress of the GaN films were evaluated at 80–800 °C without changing plasma discharge conditions. The deposited GaN films tend to be preferentially oriented on the (0002) plane at all substrate temperature ranges. The in-plane φ-scans of x-ray diffraction measurements showed sixfold symmetric diffraction patterns of GaN(10−10) above 200 °C. At 800 °C, the film stress was down to one tenth compared with 80 °C and the full width at half maximum of the rocking curve at a GaN(0002) diffraction angle reached down to 1.1°. The GaN film deposition condition of 200 °C by CPSD suffices for the alignment of the twist angle of the c axis of GaN.