Initial nucleation scheme of Ga2O3 on (0001) sapphire by mist CVD for the growth of α-phase

Abstract

Abstract Recently, α-Ga2O3 has been attracting great attentions as a new wide bandgap semiconductor, however, the reason why metastable α-Ga2O3 is grown by mist chemical vapor deposition (CVD) has not been understood. In this study, in order to elucidate growth mechanism of mist CVD-grown α-Ga2O3, growth processes in the initial stage were investigated by atomic force microscopy, transmission electron microscopy, and X-ray diffraction reciprocal space mapping. We found that the characteristics of mist CVD make the relaxation mechanisms of α-Ga2O3 on (0001) sapphire different from those of molecular beam epitaxy, pulsed-laser deposition, and metalorganic chemical vapor deposition. We also proposed the growth procedure in the initial stage.