Substrates Effect on the Phase Transition of GaN Thin Films by Sputter Deposition

Abstract

As a promising third generation semiconductor material, gallium nitride (GaN) has become a research hotspot in optoelectronic field nowadays. In this paper, GaN thin films were grown by radio frequency (RF) planar magnetron sputtering of a powder GaN target in a pure nitrogen atmosphere at (0.2 – 2.0) Pa, (10 - 100) W onto various substrates such as GaAs (100), Si (100), Si (111), Al2O3(0001) and glass without any buffer layer. A clear phase transition from the metastable cubic zinc-blende (c - ZB) to the stable hexagonal wurtzite (h - WZ) dependence on substrates has been found in the GaN thin films. And the phase transition of GaN films were studied by X-ray diffraction (XRD), photoluminescence (PL) and Raman spectroscopy.