Growth kinetics of AlN and GaN films grown by molecular beam epitaxy on R-plane sapphire substrates

Journal Article · Sun Aug 15 00:00:00 EDT 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3475521· OSTI ID:21476421

Chandrasekaran, R; Moustakas, T D ^[1]; Ozcan, A S; Ludwig, K F ^[2]; Zhou, L; Smith, David J ^[3]

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1. Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215 (United States)
2. Physics Department, Boston University, Boston, Massachusetts 02215 (United States)
3. Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

This paper reports the growth by molecular beam epitaxy of AlN and GaN thin films on R-plane sapphire substrates. Contrary to previous findings that GaN grows with its (1120) A-plane parallel to the (1102) R-plane of sapphire, our results indicate that the crystallographic orientation of the III-nitride films is strongly dependent on the kinetic conditions of growth for the GaN or AlN buffer layers. Thus, group III-rich conditions for growth of either GaN or AlN buffers result in nitride films having (1120) planes parallel to the sapphire surface, and basal-plane stacking faults parallel to the growth direction. The growth of these buffers under N-rich conditions instead leads to nitride films with (1126) planes parallel to the sapphire surface, with inclined c-plane stacking faults that often terminate threading dislocations. Moreover, electron microscope observations indicate that slight miscut ({approx}0.5 deg. ) of the R-plane sapphire substrate almost completely suppresses the formation of twinning defects in the (1126) GaN films.

• OSTI ID: 21476421
• Journal Information: Journal of Applied Physics, Vol. 108, Issue 4; Other Information: DOI: 10.1063/1.3475521; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM NITRIDES
CRYSTAL GROWTH
CRYSTALS
DISLOCATIONS
ELECTRON MICROSCOPY
GALLIUM NITRIDES
LAYERS
MOLECULAR BEAM EPITAXY
ORIENTATION
SAPPHIRE
SEMICONDUCTOR MATERIALS
STACKING FAULTS
SUBSTRATES
SURFACES
THIN FILMS
TWINNING
ALUMINIUM COMPOUNDS
CORUNDUM
CRYSTAL DEFECTS
CRYSTAL GROWTH METHODS
CRYSTAL STRUCTURE
EPITAXY
FILMS
GALLIUM COMPOUNDS
LINE DEFECTS
MATERIALS
MICROSCOPY
MINERALS
NITRIDES
NITROGEN COMPOUNDS
OXIDE MINERALS
PNICTIDES