Growth of thick GaN layers on laser-processed sapphire substrate by hydride vapor phase epitaxy

• Published in: Journal of crystal growth 2014-10, Vol.403, p.38-42
• Main Authors: Koyama, Koji, Aida, Hideo, Kim, Seong-Woo, Ikejiri, Kenjiro, Doi, Toshiro, Yamazaki, Tsutomu
• Format: Article
• Language: English
• Subjects: A1. Cracks; A1. Defects; A1. Laser process; A3. Hydride vapor phase epitaxy; B1. Sapphire; B2. Semiconductor III–V materials; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fracture mechanics; Gallium nitrides; Laser processing; Materials science; Mathematical analysis; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Microcracks; Physics; Sapphire; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Vapor phase epitaxy; Vapor phase epitaxy; growth from vapor phase
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2014.06.010

A 600µm thick GaN layer was successfully grown by hydride vapor phase epitaxy by replacing the standard sapphire substrate with that processed by a focused laser beam within the substrate. The effects of the laser processing on the curvature and cracking of the GaN layer were investigated. Microscopic observations of the interior of the thick GaN layer revealed that the laser-processed substrate suppressed the generation of microcracks in the GaN layer. In addition, the laser processing was also found to reduce the change in the curvature during the GaN layer growth in comparison to that on the standard substrate. It is shown that the overlapping microcracks observed in the GaN layer on the standard sapphire substrate lead to serious cracking after thick GaN layer growth.