The origin of dislocations in multilayers

Abstract

Repu le 6 juin 1990, acceptJ le 4 octobre 1990) Rksumk. Cet article aborde des questions fondamentales qui concement la germination et la propagation des dislocations dans les multicouches, et en particulier dans les semiconducteurs bpitaxibs. Nous considbrons le concept d'bpaisseur critique pour l'apparition des dislocations de dbsadaptation de rbseau dans les couches contraintes. Los rbsultats de topographie X et de microscopie blectronique qui sont prbsentbs montrent que le concept d'bpaisseur critique n'est pas aussi bien dbfini qu'on le supposait auparavant. Les considbrations thboriques sur les sources des dislocations de dbsadaptation, dans les couches bpitaxibes sur des substrats sans dislocations,

Fabrication technology of SiGe hetero-structures and their properties

“…Although detailed mechanisms for misfit dislocation nucleation in SiGe/Si systems are still controversial, the phenomena generally obey either ''heterogeneous'' or ''homogeneous'' nucleation mechanism. Earlier works sought for the heterogeneous nucleation source, such as SiC precipitates formed by incomplete substrate cleaning [73], a a/4 h1 1 4i stacking fault regions [74,75], surface half-loops and faulted dislocation loops associated with metallic contamination [76,77]. However, all of these heterogeneous sites appear dependently on the growth conditions and cannot account for the strain relaxation behavior occurring in the initial stage because of their relatively low density.…”

Elemental Dislocation Mechanisms Involved in the Relaxation of Heteroepitaxial Semiconducting Systems

“…A lot of mechanisms have been proposed in GeSi/Si systems, involving growth defects such as: b-SiC precipitate plates [17], oxide particles [18], diamond defects [19,20], Ge-rich platelets [21]. A possible mechanism which could produce a high density of misfit dislocations, with identical Burgers vectors, is the one involving spiral or FrankRead sources [22], but it needs misfit dislocations developed already, pinning and crossslip processes and thus cannot be considered as a true nucleation process.…”

Strain relaxation of GeSi/Si(001) heterostructures grown by low-temperature molecular-beam epitaxy

“…40,41 The density of such centers is usually insufficient for a complete plastic relaxation of the stressed film, and the mechanisms of secondary generation (multiplication) of misfit dislocations 38,39 start to operate when the film reaches a certain critical thickness.…”