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

Abstract

In this study, epitaxial δ‐Ga2O3 thin films were successfully grown on various planes of yttria‐stabilized zirconia (YSZ) and c‐plane sapphire substrates by inserting same crystal‐structured β‐Fe2O3 and bcc‐In2O3 buffer layers via mist chemical vapor deposition. X‐ray diffraction (XRD) measurements revealed that various planes of δ‐Ga2O3 thin films were grown in both the out‐of‐plane and in‐plane orientations using the same crystal‐structured buffer layers to reduce the lattice mismatch. δ‐Ga2O3 (111) was demonstrated to grow on the YSZ (111) in the narrow growth temperature range of 575 to 675 °C due to thermal instability of β‐Fe2O3 buffer layers. Next, we investigated a c‐plane sapphire wafer as a substrate using two buffer layers for the growth of δ‐Ga2O3. XRD 2θ‐ω scan revealed that the mixture of α‐ and δ‐ Ga2O3 thin films were grown on Fe2O3/In2O3/c‐plane sapphire. This is because the Fe2O3 buffer layers were phase separated into α and β phases due to the large grain size of the In2O3 buffer layer. XRD φ‐scan profiles indicated that the δ‐Ga2O3 thin film grown on sapphire was composed of a twin domain. This study contributes to our understanding of the growth mechanism of δ‐Ga2O3 and its future applications in devices.This article is protected by copyright. All rights reserved.