Defect Characterization in SiGe/SOI Epitaxial Semiconductors by Positron Annihilation

The potential of positron annihilation spectroscopy (PAS) for defect characterization at the atomic scale in semiconductors has been demonstrated in thin multilayer structures of SiGe (50 nm) grown on UTB (ultra-thin body) SOI (silicon-on-insulator). A slow positron beam was used to probe the defect...

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Bibliographic Details
Published in:Nanoscale research letters 2010-10, Vol.5 (12), p.1942-1947
Main Authors: Ferragut, R, Calloni, A, Dupasquier, A, Isella, G
Format: Article
Language:English
Subjects:
Point defects
Positron annihilation spectroscopy
SiGe semiconductors
Ultra-thin body films
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Summary:The potential of positron annihilation spectroscopy (PAS) for defect characterization at the atomic scale in semiconductors has been demonstrated in thin multilayer structures of SiGe (50 nm) grown on UTB (ultra-thin body) SOI (silicon-on-insulator). A slow positron beam was used to probe the defect profile. The SiO₂/Si interface in the UTB-SOI was well characterized, and a good estimation of its depth has been obtained. The chemical analysis indicates that the interface does not contain defects, but only strongly localized charged centers. In order to promote the relaxation, the samples have been submitted to a post-growth annealing treatment in vacuum. After this treatment, it was possible to observe the modifications of the defect structure of the relaxed film. Chemical analysis of the SiGe layers suggests a prevalent trapping site surrounded by germanium atoms, presumably Si vacancies associated with misfit dislocations and threading dislocations in the SiGe films.
ISSN:1931-7573
1556-276X
1556-276X
DOI:10.1186/1556-276X-5-1942