2 in. Bulk ß-Ga2O3 Single Crystals Grown by EFG Method with High Wafer-Scale Quality.

ABSTRACT

2 in. bulk ß-Ga2O3 single crystals are successfully grown by the edge-defined film-fed growth method with a homemade furnace system. By considering the significance of wafer quality in future mass manufacture, a nine-point characterization method is developed to evaluate the full-scale quality of the processed 2 in. (100)-orientated ß-Ga2O3 single-crystal wafers. Crystalline and structural characteristics were evaluated using X-ray diffraction and Raman spectroscopy, revealing decent crystalline quality with a mean full width at half-maximum value of 60.8 arcsec and homogeneous bonding structures. The statistical root-mean-square surface roughness, determined from nine scanning areas, was found to be only 0.196 nm, indicating superior surface quality. Linear optical properties and defect levels were further investigated using UV-visible spectrophotometry and photoluminescence spectroscopy. The high wafer-scale quality of the processed ß-Ga2O3 wafers meets the requirements for homoepitaxial growth substrates in electronic and photonic devices with vertical configurations.