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RESEARCH PRODUCT

Point-defect mediated diffusion in intrinsic SiGe-alloys

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The aim of this thesis was to obtain fundamental diffusion data and to improve the understanding of point-defect mediated dopant diffusion in Si1- xGex alloys. The thesis consists of experimental studies published in international journals and a summary section. The experimental part consists of the following four articles: In article I, diffusion coefficients and Arrhenius parameters have been determined in relaxed intrinsic Si1-xGex in the whole concentration range (0<x<1). In article II, diffusion coefficients and Arrhenius parameters have been determined for Ga and Sn diffusion in relaxed intrinsic and relaxed heavily p-doped germanium. In article III, diffusivity values have been determined for Ga in relaxed intrinsic Si1-xGex in the whole concentration range at 907 ºC. In article IV, diffusion coefficients and Arrhenius parameters have been determined for Si in intrinsic B20-structured FeSi. All the experiments discussed employed the modified radiotracer technique. The radioactive tracers were produced at the IGISOL facility located in Jyväskylä, Finland (31Si and 66Ga) and at the ISOLDE facility located in CERN, Switzerland (123Sn). In the summary section, an attempt has been made to understand the diffusion behavior of substitutionally solved group III, IV and V elements in Si1-xGex alloys based on point-defect transport capacities and properties of pointdefect- impurity interactions. The dissection is based on best available literature data as well as the data obtained during this study (articles I-IV).