Influence of Al/N flux ratio during nucleation layer growth on the structural properties of AlN grown on sapphire by molecular beam epitaxy

Journal Article · Mon Oct 17 04:00:00 EDT 2005 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2093923· OSTI ID:20706373

Faelth, J F; Davidsson, S K; Liu, X Y; Andersson, T G ^[1]

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1. Applied Semiconductor Physics-MBE, Department of Microtechnology and Nanoscience, Chalmers University of Technology and Goeteborg University, S-412 96 Goeteborg (Sweden)

AlN nucleation and buffer layers have been grown with different Al/N flux ratio by molecular beam epitaxy on sapphire. Thick AlN on top of a nucleation layer grown with Al/N flux ratio=1.0 exhibited deep hexagonal holes (diameter 100-200 nm, density {approx}10{sup 9} cm{sup -2}). Investigation of the nucleation layer surface revealed that the holes were formed already during the nucleation. The formation of holes in AlN buffer layers could be avoided by using a N-rich (Al/N=0.5) nucleation layer. It is demonstrated that the holes in AlN buffer layers can be effectively avoided choosing a N-rich nucleation layer growth and then switch to Al/N flux ratio =1.0 for buffer layer growth. The two-step AlN growth gave high quality AlN, with excellent crystalline quality and smooth surface.

• OSTI ID: 20706373
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 16 Vol. 87; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM NITRIDES
CRYSTAL GROWTH
LAYERS
MOLECULAR BEAM EPITAXY
NANOSTRUCTURES
SAPPHIRE
SEMICONDUCTOR MATERIALS