Controlled coalescence of MOVPE grown AlN during lateral overgrowth

• Published in: Journal of crystal growth 2013-04, Vol.368, p.83-86
• Main Authors: Kueller, V., Knauer, A., Zeimer, U., Kneissl, M., Weyers, M.
• Format: Article
• Language: English
• Subjects: A1. In-situ characterization; A1. Substrate miscut; A3. Metalorganic vapor phase epitaxy; A3. Pendeoepitaxy; A3. V/III ratio; Aluminum nitride; B1. Nitrides; Coalescence; Coalescing; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystal growth; Epitaxial growth; Exact sciences and technology; Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Orientation; Physics; Reflectivity; Sapphire; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; Thin film structure and morphology; Vapor phase epitaxy; growth from vapor phase
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2013.01.028

The substrate miscut orientation of c-plane sapphire has an impact on the lateral growth and coalescence of AlN during epitaxial lateral overgrowth of patterned AlN/sapphire templates. A faster and more homogeneous coalescence was observed for substrates with a miscut orientation of 0.25° toward the m-direction compared to 0.25° toward the a-direction of the sapphire. A reduction of V/III ratio during overgrowth leads to an increase of lateral growth rate and therefore to a faster coalescence. The layer thickness at coalescence was clearly determined by in-situ reflectance measurements during the overgrowth. The coalescence can be controlled by carefully choosing the parameters influencing lateral growth like substrate miscut, process temperature and V/III ratio. ► AlN epitaxial lateral overgrowth has been performed successfully. ► Faster and more homogeneous coalescence for sapphire miscut 0.25° m compared to 0.25° a. ► A low V/III ratio increases the lateral growth rate. ► Coalescence thickness is clearly determinable in-situ.