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Comparison of cross-sectional transmission electron microscope studies of thin germanium epilayers grown on differently oriented silicon wafers.
Norris, D J; Myronov, M; Leadley, D R; Walther, T.
Afiliación
  • Norris DJ; Kroto Centre for High-Resolution Imaging and Analysis, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, U.K.
  • Myronov M; Department of Physics, University of Warwick, Coventry, U.K.
  • Leadley DR; Department of Physics, University of Warwick, Coventry, U.K.
  • Walther T; Kroto Centre for High-Resolution Imaging and Analysis, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, U.K.
J Microsc ; 268(3): 288-297, 2017 12.
Article en En | MEDLINE | ID: mdl-28972660
We compare transmission electron microscopical analyses of the onset of islanding in the germanium-on-silicon (Ge/Si) system for three different Si substrate orientations: (001), (11¯0) and (11¯1)Si. The Ge was deposited by reduced pressure chemical vapour deposition and forms islands on the surface of all Si wafers; however, the morphology (aspect ratio) of the deposited islands is different for each type of wafer. Moreover, the mechanism for strain relaxation is different for each type of wafer owing to the different orientation of the (111) slip planes with the growth surface. Ge grown on (001)Si is initially pseudomorphically strained, yielding small, almost symmetrical islands of high aspect ratio (clusters or domes) on top interdiffused SiGe pedestals, without any evidence of plastic relaxation by dislocations, which would nucleate later-on when the islands might have coalesced and then the Matthews-Blakeslee limit is reached. For (11¯0)Si, islands are flatter and more asymmetric, and this is correlated with plastic relaxation of some islands by dislocations. In the case of growth on (11¯1)Si wafers, there is evidence of immediate strain relaxation taking place by numerous dislocations and also twinning. In the case of untwined film/substrate interfaces, Burgers circuits drawn around certain (amorphous-like) regions show a nonclosure with an edge-type a/4[1¯12] Burgers vector component visible in projection along [110]. Microtwins of multiples of half unit cells in thickness have been observed which occur at the growth interface between the Si(11¯1) buffer layer and the overlying Ge material. Models of the growth mechanisms to explain the interfacial configurations of each type of wafer are suggested.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Tipo de estudio: Prevalence_studies Idioma: En Revista: J Microsc Año: 2017 Tipo del documento: Article Pais de publicación: Reino Unido
Texto completo
Añadir a Mi BVS
Imprimir
XML
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Tipo de estudio: Prevalence_studies Idioma: En Revista: J Microsc Año: 2017 Tipo del documento: Article Pais de publicación: Reino Unido