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MOVPE growth and characterization of a ‐plane AlGaN over the entire composition range
Author(s) -
Laskar Masihhur R.,
Ganguli Tapas,
Rahman A. A.,
Shah A. P.,
Gokhale M. R.,
Bhattacharya Arnab
Publication year - 2010
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201004091
Subject(s) - metalorganic vapour phase epitaxy , nucleation , sapphire , materials science , epitaxy , mosaicity , crystallography , diffraction , orthorhombic crystal system , characterization (materials science) , analytical chemistry (journal) , chemistry , layer (electronics) , optics , crystal structure , nanotechnology , physics , organic chemistry , chromatography , laser
Abstract We report the metal organic vapor phase epitaxy (MOVPE) growth and characterization of non‐polar (11 $ \bar 2 $ 0) a ‐plane Al x Ga 1– x N on (1 $ \bar 1 $ 02) r ‐plane sapphire substrates over the entire composition range. Al x Ga 1– x N samples with ∼0.8 μm thick layers and with x = 0, 0.18, 0.38, 0.46, 0.66, and 1.0 have been grown on r ‐plane sapphire substrates. The layer quality can be improved by using a 3‐stage AlN nucleation layer and appropriate V/III ratio switching following nucleation. All a ‐plane AlGaN epilayers show an anisotropic in‐plane mosaicity, strongly influenced by Al incorporation and growth conditions. Careful lattice parameter measurements show anisotropic in‐plane strain that results in an orthorhombic distortion of the hexagonal unit cell, making Al composition determination from X‐ray diffraction difficult. In general lower Al incorporation is seen in a ‐plane epilayers compared to c ‐plane samples grown under the same conditions. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)