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Stress‐dislocation management in MOVPE of GaN on SiC wafers
Author(s) -
Rudinsky M. E.,
Yakovlev E. V.,
Lundin W. V.,
Sakharov A. V.,
Zavarin E. E.,
Tsatsulnikov A. F.,
Velikovskiy L. E.
Publication year - 2016
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201600210
Subject(s) - materials science , dislocation , nucleation , wafer , epitaxy , metalorganic vapour phase epitaxy , stress relaxation , stress (linguistics) , curvature , gallium nitride , composite material , optoelectronics , condensed matter physics , layer (electronics) , geometry , chemistry , creep , linguistics , organic chemistry , philosophy , mathematics , physics
A combined experimental and modeling study of stress and curvature evolution during (0001) GaN growth on (0001) 4H‐SiC wafers is presented. It is shown that the GaN layers are under the compressive stress, whose magnitude depends on the composition of the AlGaN buffer that is used to accommodate the epitaxial strain between GaN and SiC. Processing of in situ curvature measurements suggests fast relaxation of the mismatch stress in GaN when the Al content is increased. At that, nucleation of new dislocations is possible, but the dislocation density decreases rapidly over a narrow part of the GaN layer due to large inclination and annihilation of the threading dislocations. Eventually, correlations between the curvature/stress/dislocation evolution and AlGaN buffer composition can be established and optimal strategy for the growth of crack‐free structures can be suggested.