Influence of the misorientation of 6H–SiC substrate on the quality of GaN epilayer grown by MOVPE

• Published in: Journal of alloys and compounds 2011-02, Vol.509 (8), p.3656-3660
• Main Authors: Qu, Shuang, Wang, Chengxin, Li, Shuqiang, Xu, Xiangang, Shao, Huihui, Peng, Yan, Gao, Yuqiang, Chen, Xiufang, Hu, Xiaobo
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Density; Dislocation density; Edge dislocations; Etching; Exact sciences and technology; Gallium nitrides; Luminescence; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Misorientation; Nitrides; Organometallic vapor phase epitaxy; Physics; Semiconducting silicon compounds; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory and models of film growth; Thin film structure and morphology; Vapor phase epitaxy; Vapor phase epitaxy; growth from vapor phase
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2010.12.150

▶ Larger substrate misorientation results in better crystal quality of GaN epilayer. ▶ The dislocations density was influenced not only by the misorientation angle but also by the misorientation direction, while the point defects were affected only by the misorientation angle. ▶ GaN grown on 6H–SiC substrate with 2.3° misorientation angle and [1 1 2¯ 0] misorientation direction has the best crystal quality. The effect of misorientation of 6H–SiC substrate on the structural quality of GaN epilayer grown by organometallic vapor phase epitaxy (MOVPE) has been investigated. The results reveal that the structural quality of GaN epilayer is significantly influenced by the misorientation of 6H–SiC substrate. Larger misorientation angle of 6H–SiC substrate results in better structural quality of GaN epilayer, such as narrower atomic step widths of GaN surface, less yellow luminescence band/edge emission (Iy/Ib) ratio of PL, and lower dislocations density. It is also found that the Iy/Ib ratio of GaN epilayer is affected only by the misorientation angle of 6H–SiC substrate, but the screw dislocation density and edge dislocation density are influenced by both the misorientation angle and the misorientation direction of 6H–SiC substrate. GaN epilayer grown on 6H–SiC substrate with 2.3° misorientation angle towards [1 1 2¯ 0] direction has the best structural quality.