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TEM Study of the Behavior of Dislocations during ELO of GaN
Author(s) -
Bousquet V.,
Vennéguès P.,
Beaumont B.,
Vaille M.,
Gibart P.
Publication year - 1999
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/(sici)1521-3951(199911)216:1<691::aid-pssb691>3.0.co;2-8
Subject(s) - materials science , metalorganic vapour phase epitaxy , coalescence (physics) , sapphire , epitaxy , dislocation , transmission electron microscopy , optoelectronics , basal plane , bending , condensed matter physics , optics , crystallography , composite material , nanotechnology , laser , chemistry , layer (electronics) , physics , astrobiology
We study by transmission electron microscopy (TEM) the mechanisms of the defect reduction in metalorganic vapor phase epitaxy (MOVPE) ELO of GaN on a sapphire substrate. A first growth step induces the bending of the dislocations and thus allows a drastic reduction of the density of vertically threading defects. In the second step, the dislocations keep their line in the basal plane and propagate horizontally towards the coalescence boundary with the GaN material coming from the adjacent window. We describe their different behaviors in the boundary. Finally, plan view observations reveal that large areas are free of dislocations at the TEM scale.