Contactless processing of SiGe-melts in EML under reduced gravity
The processing of semiconductors based on electromagnetic levitation is a challenge, because this kind of materials shows a poor electrical conductivity. Here, we report the results of measurements of the thermophysical properties obtained recently from highly doped semiconductors Si Ge under microg...
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Published in | NPJ microgravity Vol. 2; no. 1; pp. 1 - 9 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Nature Publishing Group
16.12.2016
Nature Publishing Group UK Nature Portfolio |
Subjects | |
Online Access | Get full text |
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Summary: | The processing of semiconductors based on electromagnetic levitation is a challenge, because this kind of materials shows a poor electrical conductivity. Here, we report the results of measurements of the thermophysical properties obtained recently from highly doped semiconductors Si
Ge
under microgravity conditions in the framework of parabola flight campaigns. Due to the limited time of about 20 s of microgravity especially Ge-rich samples with low melting temperatures were investigated. The measurements were performed contactlessly by video techniques with subsequent digital image processing. Linear and volume thermal expansion coefficients were measured hereby from image data. An anomaly of volume changes near the solidus temperature is visible. Viscosity and surface tension were determined by the oscillating drop technique using optic and electronic data. It was observed that the alloying of Si into Ge increases the surface tension of the melts. The viscosity is following an Arrhenius equation and shows a crossover temperature which separates simple liquid at high temperatures from cooperative liquid at low temperatures. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2373-8065 2373-8065 |
DOI: | 10.1038/s41526-016-0007-3 |