Understanding Thickness Uniformity of Ga₂O₃ Thin Films Grown by Mist Chemical Vapor Deposition

Abstract

α–Ga2O3 thin films were grown on a c–plane sapphire substrate by mist chemical vapor deposition in a horizontal furnace. The microstructure of the α–Ga2O3 grown layers was confirmed by X-ray diffraction. The effects of the temperature distribution and velocity field of the mist flow at the surface of the substrate on the uniformity of the epitaxy layers were revealed by numerical simulations and experimental measurements. The thickness uniformity of the thin film was found to be dependent on the position of the inlet and on the flow rate. The suggested configuration for obtaining highly uniform Ga2O3 epilayers is a low flow rate of less than 0.1 m/s and the flow directed from the bottom of the substrate to the top surface of the substrate.