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The use of synchrotron edge topography to study polytype nearest neighbour relationships in SiC

Kelly, Jim and Barnes, Paul and Fisher, G.R. (1995) The use of synchrotron edge topography to study polytype nearest neighbour relationships in SiC. Radiation Physics and Chemistry 45 (3), pp. 509-522. ISSN 0969-806X.


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A brief review of the phenomenon of polytypism is presented and its prolific abundance in Silicon Carbide discussed. An attempt has been made to emphasise modern developments in understanding this unique behaviour. The properties of Synchrotron Radiation are shown to be ideally suited to studies of polytypes in various materials and in particular the coalescence of polytypes in SiC. It is shown that with complex multipolytypic crystals the technique of edge topography allows the spatial extent of disorder to be determined and, from the superposition of Laue type reflections, neighbourhood relationships between polytypes can be deduced. Finer features have now been observed with the advent of second generation synchrotrons, the resolution available enabling the regions between adjoining polytypes to be examined more closely. It is shown that Long Period Polytypes and One Dimensionally Disordered layers often found in association with regions of high defect density are common features at polytype boundaries. An idealised configuration termed a "polytype sandwich" is presented as a model for the structure of SiC grown by the modified Lely technique. The frequency of common sandwich edge profiles are classified and some general trends of polytype neighbourism are summarised.

Item Type: Article
Keyword(s) / Subject(s): Semiconductors, Crystal growth, X-ray diffraction
School or Research Centre: Birkbeck Schools and Research Centres > School of Science > Biological Sciences
Depositing User: Dr. Jim Kelly
Date Deposited: 17 Jul 2006
Last Modified: 17 Apr 2013 12:32

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