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Methods of Preparation of GeSi‐Alloys
Author(s) -
Dietz W. H.,
Herrmann H. A.
Publication year - 1969
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19690040312
Subject(s) - homogeneity (statistics) , materials science , homogeneous , phase diagram , crucible (geodemography) , thermoelectric effect , crystallization , silicon , thermal , crystal (programming language) , phase (matter) , thermodynamics , metallurgy , chemistry , computer science , physics , computational chemistry , organic chemistry , programming language , machine learning
Abstract The production of homogeneous alloys of Ge and Si is very difficult because of an unfavourable phase diagram which is briefly described. One has to distinguish between processes for the preparation of single crystals and polycrystals sufficiently applicable for technical purposes. In order to produce polycrystals suitable for thermoelectric generators the following methods were investigated: Thermal Decomposition, Zone Levelling, Hot‐Pressing, and the new Wacker‐Process. The latter has its basic principle in the rapid crystallization of small portions of a doped homogeneous GeSi‐melt in a crucible. The solidification of mixed crystals is not only subject to the laws of phase equilibrium but also to kinetic conditions. In the new process GeSi can be produced economically in different shapes. Two problems arise in the preparation of single crystals: availability of a seed crystal and constant homogeneity of the melt. In order to solve these problems we tried Zone Levelling which seemed to be the simplest method, but we also pulled single crystals from crucibles, keeping the composition of the melt constant by continuously adding silicon.