Crystal Quality Improvement of α-Ga2O3 Growth on Stripe Patterned Template via Epitaxial Lateral Overgrowth

Abstract

Among the Ga2O3 polymorphs, which are ultrawide-band-gap materials, α-Ga2O3 undergoes only heteroepitaxial growth and has been actively studied for producing high-quality thin films. However, attaining a high-quality film via heteroepitaxial growth is difficult owing to both the lattice mismatch between sapphire and Ga2O3 and the difference in their thermal expansion coefficients. To overcome this problem, epitaxial lateral overgrowth, which improves the quality of epitaxial growth, was employed to grow the α-Ga2O3 epilayer. In addition, samples grown along the [112̅0] and [11̅00] directions were compared by analyzing the X-ray rocking curve of the 0006 and 101̅4 diffractions to investigate the characteristics of lateral growth. The α-Ga2O3 grown via halide vapor phase epitaxy showed a relatively high lateral growth rate along the [11̅00] pattern direction. The full width at half-maximum of the 101̅4 diffraction of α-Ga2O3 grown along the [11̅00] direction was measured to be 757 arcsec, which was remarkably lower than that of conventionally grown α-Ga2O3.