A study on the technical improvement and the crystalline quality optimization of columnar β-Ga2O3 crystal growth by an EFG method

High quality columnar beta-Ga(2)O(3)crystals were successfully grownviaan edge-defined film-fed growth (EFG) method equipped with columnar Ir die. The effects of the pulling rate and die height on the structural quality and crystal shape of beta-Ga(2)O(3)are summarized and discussed in detail. The main problems of spiral and polycrystal formation and incomplete columnar quality in the beta-Ga(2)O(3)crystal growth were solved successfully. Suitable values for the growth parameters such as pulling rate and Ir height were determined to be in the range between 2-10 mm h(-1)and 30-40 mm (0.6-0.8 mm longer than the crucible height), respectively. Simultaneously, the die diameter should be 25 mm (0.5 mm wider than the crucible diameter) to obtain columnar beta-Ga(2)O(3)crystals in good quality. Furthermore, the crystalline quality of the as-grown crystal was confirmedviahigh-resolution X-ray diffraction (HRXRD) with a full-width at half-maximum (FWHM) of 69.3 arcsec. The defects of beta-Ga(2)O(3)were studiedviaa chemical etching method. Two types of etch pits were observed: (1) a triangle-shaped etch pit and (2) a quadrangle-shaped etch pit. The average defect density was estimated at a lower order of magnitude of -10(4)cm(-2).