Fabrication of low-curvature 2 in. GaN wafers by Na-flux coalescence growth technique

Low-curvature and large-diameter GaN wafers are in high demand for the development of GaN-based electronic devices. Recently, we have proposed the coalescence growth of GaN by the Na-flux method and demonstrated the possibility of enlarging the diameter of high-quality GaN crystals. In the present study, 2 in. GaN wafers with a radius of curvature larger than 100 m were successfully produced by the Na-flux coalescence growth technique. FWHMs of the 002 and 102 GaN X-ray rocking curves were below 30.6 arcsec, and the dislocation density was less than the order of 102 cm−2 for the entire area of the wafer.