Impact of α-Fe₂O₃ Buffer Layer Growth Time on the α-Ga₂O₃ Grown on LiTaO₃ Substrates

Abstract

Corundum structured α-Ga2O3 is a promising semiconductor material for power switching devices due to its large bandgap (5.3 eV). The high dislocation density of α-Ga2O3 caused by a large lattice mismatch between the α-Ga2O3 and a sapphire substrate is a significant issue to a high-reliability operation. We featured LiTaO3 substrates exhibiting a near corundum structure as growth substrates to decrease the lattice mismatch. Our previous study revealed that the growth of α-Ga2O3 on LiTaO3 substrates required α-Fe2O3 buffer layers. In this study, the impact of α-Fe2O3 buffer layer growth time on the growth of α-Ga2O3 was investigated. X-ray diffraction 2θ-ω analysis revealed that α-Ga2O3 was successfully grown by inserting α-Fe2O3 buffer layer regardless of the buffer layer growth time. The growth time of the α-Fe2O3 buffer layer affected the number of edge dislocations examined by XRD rocking curve (XRC) measurements. The smallest full width at half maximum of XRC measurements at (0006) plane of the α-Ga2O3 with the buffer layer growth time of 1min was 60 arcsec. The α-Ga2O3 with the buffer layer growth time of 1 min had a smooth surface. This study contributes power switching device application of α-Ga2O3 grown on LiTaO3 substrates.