Rapid epitaxy of 2-inch and high-quality α-Ga2O3 films by mist-CVD method

High thickness uniformity and large-scale films of alpha-Ga2O3 are crucial factors for the development of power devices. In this work, a high-quality 2-inch alpha-Ga2O3 epitaxial film on c-plane sapphire substrates was prepared by the mist-CVD method. The growth rate and phase control mechanisms were systematically investigated. The growth rate of the alpha-Ga2O3 films was limited by the evaporation of the microdroplets containing gallium acetylacetonate. By adjusting the substrate position (z) from 80 to 50 mm, the growth rate was increased from 307 nm/h to 1.45 mu m/h when the growth temperature was fixed at 520 degrees C. When the growth temperature exceeded 560 degrees C, epsilon-Ga2O3 was observed to form at the edges of 2-inch sapphire substrate. Phase control was achieved by adjusting the growth temperature. When the growth temperature was 540 degrees C and the substrate position was 50 mm, the full-width at half maximum (FWHM) of the rocking curves for the (0006) and (10-14) planes were 0.023 degrees and 1.17 degrees. The screw and edge dislocations were 2.3 x 10(6) and 3.9 x 10(10) cm(-2), respectively. Furthermore, the bandgaps and optical transmittance of alpha-Ga2O3 films grown under different conditions were characterized utilizing UV-visible and near-IR scanning spectra.

Automated summary

In this study, a high-quality 2-inch alpha-Ga2O3 epitaxial film on c-plane sapphire substrates was prepared using the mist-CVD method. The growth rate and phase control mechanisms were investigated. It was found that the growth rate of the alpha-Ga2O3 films was limited by the evaporation of the microdroplets containing gallium acetylacetonate. Phase control was achieved by adjusting the growth temperature. Additionally, the bandgaps and optical transmittance of the alpha-Ga2O3 films grown under different conditions were characterized using UV-visible and near-IR scanning spectra.