| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Materials Research in Reduced Gravity
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| Presentation Title |
Measurement of Diffusion Coefficients of Dopants in Ge and Si Melts |
| Author(s) |
Aleksandar G. Ostrogorsky, Martin Volz, Arne Croell |
| On-Site Speaker (Planned) |
Aleksandar G. Ostrogorsky |
| Abstract Scope |
The values of diffusion coefficients of dopants in semiconductor melts (“D values”) are so low, that even a minute level of convection will disturb a measurement. On Earth, this is true even for measurements conducted in fine capillaries and shear cells. The unavoidable buoyancy-driven convection inflates the D values. Thus, microgravity presents an ideal environment for experiments intended to yield the diffusion coefficients. For example, the crystal growth experiment conducted during the Apollo-Soyuz mission gave the diffusion coefficient of Ga in molten germanium, obtained by fitting the Tiller’s equation to the Ga redistribution profile.
For silicon melts, all D values reported so far were obtained on Earth. Turovskii (1962), and Kodera (1963) fitted the BPS equation to the dopant redistribution profiles, in crystals grown by the Czochralski (CZ) process. Shaskov and Gurevich (1967) used the capillary-reservoir method and obtained drastically different values.
Acknowledgements: This project is supported by the NASA Research Announcement “Research Opportunities in Materials Science – MaterialsLab Open Science Campaigns for Experiments on the International Space Station,” NNH15ZTT002N. |
| Proceedings Inclusion? |
Planned: Publication Outside of TMS |