Crystal quality and oxygen incorporation in ultra-high-rate GaN growth through oxide vapor-phase epitaxy

The relationship between crystal quality and growth rate, as well as the effect of growth temperature, was investigated for Gallium nitride (GaN) growth using oxide vapor-phase epitaxy under conditions of increased Ga2O flow. The Ga2O flow rate was set to approximately seven times the maximum value previously reported by our group, and the growth rate was increased by increasing the NH3 flow rate. At a growth temperature of 1286 °C, the crystal quality deteriorated with increasing growth rate. In contrast, at a higher growth temperature of 1320 °C, the crystal quality was maintained, and a maximum growth rate of 1.03 mm/h was achieved. However, the oxygen concentration also increased with increasing growth rate, and pronounced cracks and voids appeared when it exceeded 2 × 1021 cm−3, causing significant degradation of crystal quality. Notably, even at comparable growth rates, the oxygen concentration decreased with increasing growth temperature. These results indicate that high-temperature growth is effective for further enhancing the growth rate while suppressing oxygen incorporation and maintaining crystal quality, demonstrating the potential of oxide vapor-phase epitaxy for millimeter-per-hour-class bulk GaN growth.