摘要
为了确定Cz单晶硅生长各种驱动力对熔体对流及固/液界面形状的影响,利用CGSim软件,对典型的Cz单晶硅生长中的熔体对流进行数值模拟。研究了重力、表面张力、平流力、晶转、埚转和氩气剪切力等各种驱动力的大小对熔体对流涡胞、涡胞强度、界面形状、温度分布的影响。结果表明：各种驱动力对熔体对流的影响大小依次为：浮力〉表面张力〉晶转力〉氩气剪切力〉埚转力〉平流力;浮力和表面张力使熔体产生一沿坩埚壁上升、从固/液界面附近下降的涡胞,晶转力和氩气剪切力使熔体产生与前面反方向的涡胞,而埚转力产生多个不同流向的对流涡胞,使熔体混合更加均匀,熔体凝固引起的平流力对熔体对流影响不大;增大埚转,熔体中涡胞数量更多、对流换热更充分、温度梯度更小、熔体内的最高温度更低,有利于减少石英坩埚氧的熔解,但界面更向下凹;增大晶转,熔体内的最高温度无明显变化;固定埚转Ωc=-10 r/min,晶转存在一临界值Ωs（C）=60~80 r/min,当Ωs〈Ωs（C）时,增大晶转,固/液界面更向上凹,当Ωs〉Ωs（C）时,增大晶转,固/液界面更向下凹。
In order to study on the effects of different driving forces on melt convection and on the shape of the crystal / melt interface in Cz-Si growth,numerical simulation of melt convection is provided for typical Cz furnace and growth conditions in solar photovoltaic industry by using CGSim software. By changing the intensity of different driving forces,such as buoyancy,surface tension,advection,crystal rotation, crucible rotation and Ar shear force,the influence of each driving force on the convection structure, interface shape and temperature distribution in Si melt are obtained. From the modeling results it is found that the influence order for driving forces on the melt convection from strong to weak is： buoyancy ＆gt; surface tension ＆gt; crystal rotation ＆gt; Ar shear force ＆gt; crucible rotation ＆gt; advection. Considering crystal / meltinterface shape,buoyancy and surface tension make the interface more concave-up; crystal rotation and Ar shear force make it more concave-down; crucible rotation has no marked effect on interface shape. There exists a theoretical critical value for the crystal rotation rate,Ωs（C） =60 ~80 r/min. When Ωs＆lt; Ωs（C）,increasing crystal rotation will result in the interface more concave-up; when Ωs＆gt; Ωs（C）, increasing crystal rotation will result in the interface more concave-down.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2014年第4期903-911,共9页
Journal of Synthetic Crystals
基金
国家自然科学基金青年基金(51206069)
高等学校博士学科点专项科研基金(20123227120017)
江苏省自然科学基金青年基金(BK2012295)
江苏大学高级专业人才科研启动基金(1281130015)
江苏省博士后科研资助计划(1301049C)
关键词
晶体生长
Cz硅
数值模拟
熔体对流
固
液界面
crystal growth
Cz-Si
numerical simulation
melt convection
crystal /melt interface
