Reduced critical thickness for relaxing heteroepitaxial films on compliant substrates

It is argued that heteroepitaxial thin films (layers) grown on a compliant substrate are not able to relax their strain elastically by large-area slip across a “weak” layer. Instead, the Matthews model of plastic relaxation is modified by supposing that the interfacial misfit dislocations relax thei...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Applied physics letters 2003-05, Vol.82 (19), p.3209-3211
Hauptverfasser: Kästner, G., Gösele, U.
Format: Artikel
Sprache:eng
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:It is argued that heteroepitaxial thin films (layers) grown on a compliant substrate are not able to relax their strain elastically by large-area slip across a “weak” layer. Instead, the Matthews model of plastic relaxation is modified by supposing that the interfacial misfit dislocations relax their strain field or even disappear into the weak layer. Consequently, the moving film-threading dislocations experience a reduced drag force. Therefore, the critical film thickness is lowered, in contrast to the enhanced thickness predicted by current theories. A quantitative estimate is given which depends on the nature of the weak layer. Implications include a larger free slip path and potentially a lower density of film-threading dislocations.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.1573355