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Deep levels associated with dislocation annihilation by Al pre‐seeding and silicon delta doping in GaN grown on Si(111) substrates
Author(s) -
Soh C. B.,
Zang K. Y.,
Wang L. S.,
Chow S. Y.,
Chua S. J.
Publication year - 2008
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.200723481
Subject(s) - dislocation , materials science , silicon , metalorganic vapour phase epitaxy , doping , substrate (aquarium) , layer (electronics) , crystallography , annihilation , condensed matter physics , optoelectronics , nanotechnology , composite material , chemistry , epitaxy , physics , oceanography , quantum mechanics , geology
The introduction of Si burst during the growth of GaN film on Si(111) substrate by MOCVD formed a Si x N y layer which leads to an effective reduction in the density of screw dislocations. The reduction is associated with bending of screw dislocations to form a square dislocation loop when neighbouring dislocations with opposite Burger's vector paired up. The concentration of electron traps E c – E t ∼0.17–0.26 eV which is associated with screw dislocations is substantially reduced and a kink is left at the silicon rich position. The mixed‐edge dislocation, however, is not annihilated by the Si x N y layer. Addition of TMAl burst for the AlN growth leads to a substantial reduction in trap concentration associated with the nitrogen vacancies, V N , and antisite of nitrogen, N Al , at E c – E t ∼0.10 eV and E c – E t ∼ 0.60 eV respectively. This improves the quality of the subsequent layer of HT‐GaN grown and is useful for device fabrication. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)