Growth of Bulk GaN Single Crystals by the Pressure-Controlled Solution Growth Method

We are the first researchers to have developed the pressure-controlled solution growth (PC-SG) method. Using this method, supersaturation of growing crystals is realized by applying an over pressure without any temperature decrease. We applied this method to the growth of GaN crystals for examining the validity of the PC-SG method, using a high-pressure furnace. It was determined that the crystal growth rate increased as a function of temperature with a maximum at 1475°C under a nitrogen pressure of 0.98 GPa. The dependency of the growth rate on the Ga metal weight strongly supports the fact that the dominant growth process is by diffusion of nitrogen atoms in the Ga melt. GaN single crystals with a maximum size of 10 mm diameter were reproducibly grown by the PC-SG method and it was determined that these crystals had good crystallinity.