Unconventional ways to improve the efficiency of purification of two
different semiconductor materials of current interest, ZnO and Ge, are
described. It is shown that, by using chemically assisted vapour transport of
ZnO with carbon as a transporting agent, the degree of chemical purity of ZnO
can be increased by more than an order of magnitude. It is also found that
heating of the molten Ge in the experimentally determined narrow (about 20?C wide) temperature range in which an intense
evaporation of certain substances is observed, leads to a significant reduction
of germanium contamination. As a result, a subsequent deep purification of
pre-heat treated germanium by zone refining can be achieved at twice reduced
(as compared with “non-treated” Ge) number of passes of a boat with germanium
through the melting zones. Thus, the Ge
purification process becomes faster, cheaper and more efficient.
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