Hot-Zone Design and Analysis of Highly Efficient Czochralski Silicon Growth for Photovolatic Application
Date Issued
2004
Date
2004
Author(s)
Huang, Li-Yi
DOI
zh-TW
Abstract
Several hot-zone designs are presented for Czocharlski silicon growth for photovoltaic applications. Without sacrificing the crystal quality, a significant reduction of power and argon consumption was achieved, while the pulling rate was significantly increased. More importantly, the oxygen content was greatly reduced leading to longer minority lifetime of the wafers. According to the results of experiments and simulations, the variation of the axial oxygen distribution could be improved by gradually increasing the crucible rotation speed during the growth..
The major works of the thesis were hot-zone design and computer simulation. The experiments to prove the results of the designs were carried out by SAS. The design reported here included the radiation shield (molybdenum, graphite with different coatings, and composite cone) additional side and bottom insulations (graphite and graphite-felt), and upper side insulation. This thesis made simulations on the power consumption, interface concavity, the crucible and the heater temperature. Then, the growth experiments with the new hot-zone design were carried by SAS. Good agreement was found in the power consumption and a reference temperature near the heater between computer modeling and experimental measurements. The best hot zone design so far has let to a power consumption reduced from 59.1 kWh/kg to 17.4 kWh/kg, the pulling rate was increased from 0.8 mm/min to 1.32 mm/min, the average oxygen content was decreased from 17 ppma to 6.3 ppma, the consumption of argon was also reduced from 93.3 c.f../kg to 27.1 c.f./kg, the degradation rate of the graphite elements was greatly reduced, while, the interface concavity was still remained the same. According to the comparison of productivity, cost, and quality, our design has overtaken that by Siemens Solar Inustries(SSI).
Subjects
柴式法
缺陷
界面
質傳
矽
輻射
熱傳
電腦模擬
heat trans
computer simulation
silicon
Czochralski
SDGs
Type
thesis
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