Epitaxial Growth of δ‐Ga 2 O 3 Thin Films Grown on YSZ and Sapphire Substrates Using β‐Fe 2 O 3 Buffer Layers via Mist Chemical Vapor Deposition

• Published in: Physica status solidi. A, Applications and materials science Applications and materials science, 2024-07, Vol.221 (13)
• Main Authors: Kato, Takahiro, Nishinaka, Hiroyuki, Shimazoe, Kazuki, Yoshimoto, Masahiro
• Format: Article
• Language: English
• ISSN: 1862-6300; 1862-6319
• DOI: 10.1002/pssa.202300582

Herein, epitaxial δ‐Ga 2 O 3 thin films are successfully grown on various planes of yttria‐stabilized zirconia (YSZ) and c‐plane sapphire substrates by inserting the same crystal‐structured β‐Fe 2 O 3 and bcc‐In 2 O 3 buffer layers via mist chemical vapor deposition. X‐ray diffraction (XRD) measurements reveal that various planes of δ‐Ga 2 O 3 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. δ‐Ga 2 O 3 (111) is demonstrated to grow on the YSZ (111) in the narrow growth temperature range of 575–675 °C due to thermal instability of β‐Fe 2 O 3 buffer layers. Next, a c‐plane sapphire wafer as a substrate using two buffer layers for the growth of δ‐Ga 2 O 3 is investigated. XRD 2 θ –ω scan reveals that the mixture of α‐ and δ‐Ga 2 O 3 thin films is grown on Fe 2 O 3 /In 2 O 3 /c‐plane sapphire. This is because the Fe 2 O 3 buffer layers are phase separated into α and β phases due to the large grain size of the In 2 O 3 buffer layer. XRD φ‐scan profiles indicate that the δ‐Ga 2 O 3 thin film grown on sapphire is composed of a twin domain. This study contributes to our understanding of the growth mechanism of δ‐Ga 2 O 3 and its future applications in devices.