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Dislocation Structure of Growth Hillocks in Homoepitaxial GaN
Author(s) -
Nowak G.,
Pakuła K.,
Grzegory I.,
Weyher J.L.,
Porowski S.
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<649::aid-pssb649>3.0.co;2-x
Subject(s) - hillock , perpendicular , materials science , dislocation , hexagonal crystal system , condensed matter physics , crystallography , geometry , composite material , chemistry , physics , mathematics
Hexagonal hillocks are dominant surface defects in homoepitaxial GaN layers grown on N‐polar GaN substrates. AFM observations of the flat‐topped, hexagonal growth hillocks reveal a network of concentric atomic steps of the height of one c ‐axis lattice constant (5.6 Å). These steps are interlaced and perfectly aligned perpendicular to 〈1—100〉directions. Analysis of the step structure in the center of hillocks reveals the nature of its core. Usually it consists of one or more screw dislocations. Single screw and pairs of screw dislocations of opposite signs have been identified.