Modelling InSb Czochralski Growth
Bohun, Sean C.
(2001)
Modelling InSb Czochralski Growth.
Canadian Industrial Problem Solving Workshops > 5th IPSW [Seattle 18/5/2001 - 22/5/2001].
Full text available as: Abstract/SummaryThe dominant technique for producing large defect free crystals is known as the Czochralski method. Developed in 1916 by Jan Czochralski as a method of producing crystals of rare metals, this method is now used to produce most of the semiconductor wafers in the electronics industry.
Many aspects of this process have been investigated to gain a greater insight of the physical processes involved. We begin with the heat problem, first as a one dimensional model, then extending to a second dimension. This analysis indicates
that the temperature of the gas surrounding the crystal has a major impact on both the thermal stress experienced by the crystal and the shape of the crystal/melt interface. In contrast,variations in the heat
flux from the melt have much less of an effect.
Having investigated the temperature profiles, the analysis then focuses on the behaviour of the fluid. Scaling arguments are used to estimate the thickness of the various boundary layers and explain the main flow patterns that are experimentally observed.
Next, the shape of the meniscus is determined for various rotation rates. This analysis shows that the shape of the meniscus is relatively invariant at least at low rotation rates yet the actual vertical position of the meniscus changes readily with the rate of rotation.
After analyzing the fluid flow patterns, a model is developed for the height of the melt as a function of time. This indicates that for a crystal of constant radius the proportion of the effective pull rate due to the falling fluid level remains essentially constant over the complete growing time of the crystal. This no longer remains true if the radius of the crystal is allowed to increase at a constant rate.
| Item Type: | Study Group Report |
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| Study Group: | Canadian Industrial Problem Solving Workshops > 5th IPSW [Seattle 18/5/2001 - 22/5/2001] |
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| Company Name: | Firebird Semiconductors |
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| Industrial Sector: | Materials |
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| Additional Contributors: | Bouhennache, Tark and Fairbairn, Leslie and Frigaard, Ian and Ho, Joe and Hodge, Alex and Huang, Huaxiong and Kamali, Mahtab and Kharrazi, Mehdi H. K. and Lee, Namyong and LeVeque, Randy and Liang, Margaret and Liang, Shuqing and Marquez-Lago, Tatiana and Majdanac, Allan and Micklethwaite, W. F. and Muck, Matthias and Myers, Tim and Rasekh, Ali and Rossmanith, James and Sanaie-Fard, Ali and Stockie, John and Westbrook, Rex and Williams, J. F. and Zarestky, Jill |
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| ID Code: | 168 |
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| Deposited By: | Michele Taroni |
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| Deposited On: | 10 October 2008 |
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Problem StatementA common problem of using the Czochralski technique for producing large defect free crystals is that defects begin to appear in the crystal once the diameter of the crystal exceeds some critical value. The main objective of this study is to attempt to understand this phenomena by modelling the process mathematically. Hopefully, the model can also be used to design growth procedures that produce crystals without defects even when the diameters are greater than the critical values observed under current pull conditions. As indium antimonide (InSb) is used as an infrared detector, being able to manufacture large diameter crystals would have an immediate impact in industry. Archive Staff Only: edit this record
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