Epitaxial Growth of δ-Ga2O3 Thin Films Grown on YSZ and Sapphire Substrates Using β-Fe2O3 Buffer Layers via Mist Chemical Vapor Deposition

Herein, epitaxial delta-Ga2O3 thin films are successfully grown on various planes of yttria-stabilized zirconia (YSZ) and c-plane sapphire substrates by inserting the same crystal-structured beta-Fe2O3 and bcc-In2O3 buffer layers via mist chemical vapor deposition. X-ray diffraction (XRD) measurements reveal that various planes of delta-Ga2O3 thin films are grown in both the out-of-plane and in-plane orientations using the same crystal-structured buffer layers to reduce the lattice mismatch. delta-Ga2O3 (111) is demonstrated to grow on the YSZ (111) in the narrow growth temperature range of 575-675 degrees C due to thermal instability of beta-Fe2O3 buffer layers. Next, a c-plane sapphire wafer as a substrate using two buffer layers for the growth of delta-Ga2O3 is investigated. XRD 2 theta-omega scan reveals that the mixture of alpha- and delta-Ga2O3 thin films is grown on Fe2O3/In2O3/c-plane sapphire. This is because the Fe2O3 buffer layers are phase separated into alpha and beta phases due to the large grain size of the In2O3 buffer layer. XRD phi-scan profiles indicate that the delta-Ga2O3 thin film grown on sapphire is composed of a twin domain. This study contributes to our understanding of the growth mechanism of delta-Ga2O3 and its future applications in devices.