Variation of dislocation morphology with strain in Ge sub x Si sub 1 minus x epilayers on (100)Si
- Department of Materials Science and Engineering, The University, Liverpool (United Kingdom) Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, CA (USA)
- Department of Materials Science and Engineering, The University, Liverpool (United Kingdom) AT T Bell Laboratories, Murray Hill, NJ (USA)
- Department of Materials Science and Engineering, The University, Liverpool (United Kingdom)
A change in microstructure, including dislocation Burgers vector, length, and behavior has been observed to occur when the epilayer mismatch is varied in Ge{sub {ital x}}Si{sub 1{minus}{ital x}} layers grown on (100)Si. At low mismatches ({lt}1.5%), there is an orthogonal array of very long 60{degree} misfit dislocations. At higher mismatches ({gt}2.3%) there is an orthogonal array of short edge dislocations. At intermediate mismatches (1.5 to 2.3%) there is a mixture of 60{degree} and edge dislocations. The nature of the microstructure has a pronounced effect on the density of threading dislocations in the epilayer, which increase by a factor of {similar to}60{times} through a relatively small range of mismatch (1.7 to 2.1%, corresponding to {ital x} ranging from 0.4 to 0.5). These morphologies are discussed in the light of recent work on the sources of misfit dislocations. While mechanisms for the introduction and propagation of dislocations at low mismatch have recently been observed and explained, the high misfit case is clearly very different, i.e., surface nucleation seems to be likely in the latter case as opposed to operation of an internal source in the former. A mechanism for edge dislocation formation is proposed.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6195567
- Journal Information:
- Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 5:9; ISSN JMREE; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360602* -- Other Materials-- Structure & Phase Studies
BURGERS VECTOR
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DATA
DISLOCATIONS
EDGE DISLOCATIONS
ELEMENTS
EXPERIMENTAL DATA
GERMANIUM COMPOUNDS
GERMANIUM SILICIDES
INFORMATION
INTERFACES
LINE DEFECTS
MICROSTRUCTURE
MORPHOLOGY
NUMERICAL DATA
SEMIMETALS
SILICIDES
SILICON
SILICON COMPOUNDS
STRAINS