Correlation of Pulsed Gas Flow on Si-doped alpha-Ga2O3 Epilayer Grown by Halide Vapor Phase Epitaxy

Gallium oxide (Ga2O3) is the one of the ultra-wide-band-gap semiconductor material. The Ga2O3 semiconductor has been studied for use in highly energy efficient devices. Among its phases, the beta-phase of Ga2O3 has mainly been researched until recently. However, the alpha-phase, which has superior properties (e.g., wider band-gap and higher symmetry) has been discussed in the electronic-materials field of late. There are problems that need to be overcome in order for the alpha-phase to be a suitable electronic material; one of them is the production of high-quality thin films. This article reports the fabrication of a high-quality Si-doped alpha-Ga2O3 epilayer on alpha-Al2O3 substrate by halide vapor-phase epitaxy with the controlled pulse flow of each precursor. The alpha-Ga2O3 epilayer grown with a controlled pulse flow of O-2 has a lower full width at half maximum (FWHM; 1306 arcsec) for the 10-14 diffraction compared to the FWHM (2011 arcsec) of the as-grown sample. The pulse-flow mode of introducing Ga and O-2 strongly influences the crystal quality of alpha-Ga2O3. In the O-2-control mode, we demonstrated Si-doped alpha-Ga2O3 epilayers with higher electron mobility up to 51.57 cm(2) V-1 s(-1) and wider carrier concentrations range of 10(17) similar to 10(19) cm(-3) by improving the crystal quality. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.