Molecular beam epitaxy growth of GaN films on a tungsten carbide/Si template

Abstract

This study examined the growth of GaN layers by molecular beam epitaxy (MBE) using a tungsten carbide (WC) buffer sputtered on a Si(111) surface. The chemical stability of the WC layer against the Ga-Si interaction was verified experimentally. A low-temperature (LT) buffer is essential for the growth of single-crystal-quality, high-temperature gallium nitride (HT-GaN) on a WC surface. In addition, dislocation termination techniques, such as interface formation and the annealing of the buffer layer, were adopted to improve the crystalline quality. The HT-GaN sample grown on the annealed double-buffer-layer (AlN/GaN) revealed an X-ray diffraction full-width at half maximum, Hall carrier density, and carrier mobility of 2260 arcsecs, 4.39x10(18) cm(3), and 19.4 cm(2)/Vs, respectively. The crystalline quality of the GaN layer is discussed in comparison with previously reported GaN/sapphire samples.