Step flow growth of β-Ga2O3 films on off-axis 4H-SiC substrates by LPCVD

Abstract

In this work, β-Ga2O3 films were prepared on 4H-SiC (0001) substrates with 4° off-axis by low-pressure chemical vapor deposition (LPCVD). The crystalline structures, chemical compositions, optical properties, and surface/interface of the as-prepared films and heterostructures were all comprehensively investigated. X-ray diffraction and room temperature Raman spectrometry demonstrated β-Ga2O3 films are pure phase with highly preferential growth orientation along the (-201) plane. The Ga/O ratio estimated by X-ray photoelectron spectroscopy was 0.7, indicating the existence of Ga-O bonding. In addition, β-Ga2O3 films showed high transmittance at wavelengths over 300 nm, corresponding to an optical bandgap of about 4.88 eV. Remarkably, the growth of β-Ga2O3 films on 4H-SiC substrates with 4° off-axis followed the step-flow growth mode, reported for the first time. The relevant growth mechanism was discussed. These results demonstrated the feasible formation of heteroepitaxial growth of β-Ga2O3 films with high crystal quality and superior electrical properties on 4H-SiC substrates with off-axis angle by LPCVD, promising for applications in Ga2O3 based high power and optoelectronic devices.