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Optimizing GaN ( 11 2 ‾ 2 ) hetero‐epitaxial templates grown on ( 10 1 ‾ 0 ) sapphire
Author(s) -
Pristovsek Markus,
Frentrup Martin,
Han Yisong,
Humphreys Colin J.
Publication year - 2016
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201552263
Subject(s) - sapphire , materials science , epitaxy , transmission electron microscopy , full width at half maximum , dislocation , nucleation , stacking fault , optoelectronics , surface roughness , metalorganic vapour phase epitaxy , surface finish , crystallography , optics , layer (electronics) , nanotechnology , composite material , chemistry , laser , physics , organic chemistry
The hetero‐epitaxy of ( 11 2 ‾ 2 ) GaN on ( 10 1 ‾ 0 ) sapphire was optimized in metal–organic vapor phase epitaxy. Best results were obtained from an AlN nucleation followed by AlN and AlGaN layers, and inserting low‐temperature AlN interlayers (ILs) as well as a SiN x IL. X‐ray diffraction (XRD) of ω scans of the symmetric ( 11 2 ‾ 2 ) reflection yielded an ω FWHM < 450 ″ along [ 11 2 ‾3 ‾ ] and < 900 ″ along [ 10 1 ‾ 0 ] together with a 100 × 100 μ m2 rms roughness below 10 nm as determined by atomic force microscopy. The lowest threading dislocation density achieved was ≈ 10 9 cm− 2while the basal plane stacking fault density was in the lower 10 5 cm− 1range as determined by transmission electron microscopy. The suppression of the unwanted ( 10 1 ‾3 ‾ ) phase was lower than 1 in 10,000 as judged from XRD.