2003 Fiscal Year Final Research Report Summary
Global Simulation and Experiments on Oxygen Transport In Silicon CZ furnace
| Project/Area Number |
13450321
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
化学工学一般
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| Research Institution | Kyushu University |
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Principal Investigator |
IMAISHI Nobuyuki Kyushu University, Institute of Materials Chemistry and Engineering, Professor, 先導物質化学研究所, 教授 (60034394)
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| Co-Investigator(Kenkyū-buntansha) |
AKIYAMA Yasunobu Kyushu University, Institute of Materials Chemistry and Engineering, Research Associate, 先導物質化学研究所, 助手 (10231846)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Silicon single crystal / Czochralski furnace / oxygen mass transfer / Numerical simulation / Global analysis of flow, heat and mass transfer / Secondary flows / Concective instability |
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| Research Abstract |
In this Research project, we have developed a numerical simulation code for a global analysis of silicon Czochralski furnace based on a mathematical mode, in which we assumed axisymmetric, pseudo steady state of flow, temperature and concentration fields in the furnace. These codes were effectively runned to elucidate the role of gas phase diffusion and the Marangoni effect acting on the melt surface in the mass transfer of oxygen impurity. We have investigated the effects of axial magnetic field on the oxygen mass transfer. Further numerical Investigations have been done so as to evaluate the effect of thermophysical properties on the mass transfer.
These numerical results revealed that mass transfer of SiO in the gas phase is the largest mass transfer resistance in a small silicon Cz furnace. However, oxygen mass transfer rate is a complex function of velocity and temperature fields in the gas and melt. By installing a gas guide between the crucible and crystal, whole volume of gas fl
… More
ows along the melt surface and the gas phase mass transfer coefficient is significantly increased. This type of gas flow give rise of large share stress in the melt and changes the melt flow pattern and decrease the mass transfer rate in the melt. Numerical results indicated that temperature coefficient of surface tension is one of the important factor of determining the melt flow pattern. Detailed measurement of surface tension of silicon melt is necessary to understand the transport phenomena in silicon Cz furnace including the effect of oxygen partial pressure in gas phase.
These numerical results had been scheduled to be compared with new experimental results using a small Cz furnace which was moved from NEC company. The time of the moving was originary scheduled on 2001 but it was delayed to 2002 and further moved again to the Institute of Applied Mechanics, Kyushu University on late 2002. Since then the furnace was mostly used for oxide crystal pulling. Thus, we could not conduct detailed experiments of oxygen transport using the furnace. The numerical results were compared with few experimental results. We get confidence on our numerical results of global simulations since both results showed reasonable agreement with each other.
The results of these global simulation were reported in 5 papers on International Journals. In addition to these global analyses, we have reported 3 papers on three dimensional simulation of pattern formation in annular pools of silicon melt. We published one review article on the convective instability of melt flow in Cz furnace. Less
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Research Products
(18 results)
