中文摘要：

通过基于有限元方法的Comsol Multiphysics 4.3a软件模拟了多晶硅定向凝固过程中的热应力场,分析了炉膛内温度梯度,以及坩埚底部不同倒角半径对晶体内热应力的影响。结果表明：多晶硅晶体中存在两个高热应力区,热应力最大值出现在晶体底部边缘,其次为靠近晶体顶部边缘处。当炉腔内温度梯度从3 K/cm增加到6 K/cm时,晶体内热应力的平均值从34.18 MPa增加到了56.75 MPa,热应力的平均值增加了66.03%。随着温度梯度的增加,晶体内热应力平均值增长幅度逐渐减小。当坩埚底部倒角半径从10 mm增加到20 mm时,晶体内热应力的平均值从78.12 MPa减小到了63.25 MPa,热应力的平均值减小了19.03%。随着坩埚底部倒角半径的增加,晶体内热应力平均值减小幅度逐渐降低。

英文摘要：

The thermal stress field in the polysilicon crystal was numerical simulated during directional solidification by comsol 4.3a software. The influences of temperature gradient in the furnace as well as the different radius of curvature of crucible bottom corner on the thermal stress distribution in the polysilicon crystal were analyzed. The results show that there are two high thermal stress areas in the polysilicon crystal. The maximum thermal stress is located at the edges near the bottom of the crystal and the top of the crystal. When the temperature gradient in the furnace increases from 3 K/cm to 6 K/cm, the average thermal stress in the polysilicon crystal increases from 34.18 MPa to 56.75 MPa, increased by 66.03%. As the increase of the temperature gradient, the average thermal stress in the polysilicon crystal decreases gradually. When the radius of curvature of crucible bottom corner increases from 10 mm to 20 mm, the average thermal stress in the polysilicon crystal decreases from 78.12 MPa to 63.25 MPa, decreased by 19.03%. As the increase of the radius of curvature of crucible bottom corner, the average thermal stress in the polysilicon crystal decreases gradually.