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

• Published in: CrystEngComm 2020-08, Vol.22 (3), p.56-566
• Main Authors: Fu, Bo, Mu, Wenxiang, Zhang, Jin, Wang, Xiqiu, Zhuang, Wenchang, Yin, Yanru, Jia, Zhitai, Tao, Xutang
• Format: Article
• Language: English
• ISSN: 1466-8033
• DOI: 10.1039/d0ce00683a

High quality columnar β-Ga 2 O 3 crystals were successfully grown via an 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 β-Ga 2 O 3 are summarized and discussed in detail. The main problems of spiral and polycrystal formation and incomplete columnar quality in the β-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 β-Ga 2 O 3 crystals in good quality. Furthermore, the crystalline quality of the as-grown crystal was confirmed via high-resolution X-ray diffraction (HRXRD) with a full-width at half-maximum (FWHM) of 69.3 arcsec. The defects of β-Ga 2 O 3 were studied via a 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 . Innovative technology assessment and crystalline quality optimization of columnar β-Ga 2 O 3 crystal growth were performed via an EFG method.