摘要
获得高品质、低成本的直拉单晶硅是太阳能发电技术大面积推广应用的关键基础之一。本文采用有限元ANSYS软件模拟直拉单晶硅中液口距(导流筒下沿与液面距离,DSM)和器盖距(导流筒伸入加热器的距离,DSH)对单晶炉内气体流场和热场分布的影响。结果表明,随液口距的减小,气流对熔体液面上方的吹拂能力逐渐加强,有利于SiO的挥发;当液口距小于15 mm时,气流对熔体液面产生了扰动,不利于氧含量的降低。随器盖距的增加,一方面,熔体内轴向温度梯度逐渐减小,降低了坩埚底部的温度;另一方面,坩埚侧壁的温度也逐渐降低,特别是坩埚侧壁与坩埚底部结合处温度的降低,可以减少融入熔体中的氧。最终,将数值模拟的结果应用至拉晶生产中,获得了氧含量为1.10×1018atoms/cm3的大直径(200 mm)太阳能级单晶硅,并使单炉拉晶时间比未优化前缩短了12.7 h。
CZ-Silicon with high quality and low cost is one of the keys to scaled application in solar cell industry. The finite element method （FEM）is used to analyze the influence of DSM （Distance form the bottom of the heat shield to melt surface） and DSH （ Distance from the bottom of the heat shield to the top of the heater） on the distribution of the gas flow field and the thermal field, respectively. The results show that the flowing ability on melt surface becomes stronger with lowering DSM. This is benefit for volatilizing SiO. When DSM is less than 15 ram, the melt surface is disturbed by the gas flow, which would be hinder to decrease the oxygen. Secondly, decreased with increasing the DSH, which results the temperature gradient along the axial direction is to the temperature decreased at the bottom of the crucible. On the other hand, the temperature of the crucible wall is gradually reduced, especially in the combination part between side wall and the bottom of the crucible. It can reduce the oxygen melted from crucible. Finally, the results of numerical simulation have been applied to prepare the solar grade crystal silicon with large diameter of 200 mm. The oxygen content is 1.10×10^18atoms/cm^3 , and the pulling time for one growth cycle is less 12.7 h than the unoptimized processing parameters.
出处
《硅酸盐通报》
CAS
CSCD
北大核心
2013年第9期1921-1926,共6页
Bulletin of the Chinese Ceramic Society
基金
宁夏自治区2012科技支撑计划项目
关键词
CZ单晶硅
氧含量
气体流场
温度梯度
CZ-monocrystal silicon
oxygen concentration
gas flow field
temperature gradient
