Phase control of semi-polar (112¯2) and non-polar (112¯0) GaN on cone shaped r-plane patterned sapphire substrates

• Published in: Journal of crystal growth 2013-05, Vol.371, p.11-16
• Main Authors: Wang, Mei-Tan, Brunner, Frank, Liao, Kuan-Yung, Li, Yun-Li, Tseng, Snow H., Weyers, Markus
• Format: Article
• Language: English
• Subjects: A1. Nucleation; A3. Metalorganic chemical vapor deposition; B1. Nitrides; B2. Semiconducting III–V materials; Breaking down; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General studies of phase transitions; Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Nucleation; Other materials; Physics; Specific materials; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Vapor phase epitaxy; growth from vapor phase
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2013.01.032

The control of formation of semi-polar (112¯2) and nonpolar a-plane (112¯0) GaN phases on r-plane cone shaped patterned sapphire substrates (CPSS) by metalorganic vapor-phase epitaxy has been investigated. With a nucleation layer grown at 535°C and 200mbar, only semi-polar (112¯2) GaN is formed. Increasing the nucleation layer temperature to 965°C, only (112¯0) GaN is grown at 200mbar. At reduced reactor pressure of 60mbar, phase selectivity breaks down and semi-polar (112¯2) and non-polar (112¯0) GaN exist simultaneously. The crystalline quality of a-plane GaN on r-plane CPSS can be effectively improved using optimized growth direction control. ► Phase control of (112¯2) and (112¯0) GaN grown on r-plane CPSS is studied. ► Growth competition between (112¯2) and (112¯0) GaN is severely influenced by the nucleation temperature. ► Optimized completion of a-plane (112¯0) GaN enables a smooth surface on r-plane CPSS.