VGF法生长4英寸GaAs单晶固液界面形状和热应力的数值模拟研究  

Solid-Liquid Interface and Thermal Stress in Growth of 4-Inch VGF-GaAs Single Crystal by Numerical Simulation

作　　者：涂凡[1] 苏小平[1] 张峰燚[1] 黎建明[1] 丁国强[1] 王思爱[1] 

机构地区：[1]北京有色金属研究总院北京国晶辉红外光学科技公司,北京100088

出　　处：《稀有金属》2011年第3期388-393,共6页Chinese Journal of Rare Metals

基　　金：国家863项目(2002AAF3102)资助

摘　　要：采用专业晶体生长数值模拟软件C rysMas,模拟了垂直梯度凝固法(VGF)生长4英寸GaAs单晶过程中的固液界面形状,发现晶体在生长过程中固液界面形状经历了由凹到凸的变化。数值模拟结果表明熔体中和晶体中的轴向温度梯度之比小于0.4时,固液界面为凸向熔体,与理论推导结果一致。模拟了晶体生长过程中固液界面附近的晶体中的热应力值,发现固液界面为平界面时晶体中的热应力具有最小值。推导计算了VGF GaAs单晶生长过程中固液界面凹(凸)度的临界值,当固液界面凹(凸)度小于该值时,晶体中的热应力低于临界剪切应力。The numerical simulation was employed to simulate the solid-liquid interface shape during the 4-inch VGF-GaAs single crystal growth.It was found that the interface had experienced a deflection from concave to convex.The simulation result demonstrated that the interface would be convex to the melt when the ratio of the axial temperature gradient in the solid to that in the melt was smaller than 0.4,which was in agreement with the theory.The thermal stress in the solidification front was calculated,which was the smallest when the interface was flat.The maximum allowable deviation of the solid-liquid interface from planarity was calculated.The solidification front sustained a thermal stress which was smaller than CRSS（critical resolved shear stress） when the interface deflection was smaller than the maximum allowable deviation.

关 键 词：数值模拟 垂直梯度凝固技术 GAAS 固液界面 热应力 

分 类 号：O472[理学—半导体物理]