直拉单晶硅生长时空洞演化的相场模拟

为研究大直径直拉硅生长时空洞的演化规律,建立了与有限元模型所模拟的晶体生长温度场相结合的空洞演化相场模型,并应用该模型模拟研究了空洞形貌及其分布状态的变化过程以及不同初始点缺陷浓度对空洞演化的影响规律.结果表明:直拉硅单晶生长过程中,空洞的演化经历了孕育-形核-长大-稳定四个阶段,其形貌和分布状态亦由孤立的球形向偏聚的串珠形转变；与较低的点缺陷浓度相比,初始点缺陷浓度较高时,空洞的数目、平均尺寸、面积分数普遍较大,孕育阶段缩短、形核和长大阶段延长；空洞的偏聚及合并、长大的现象显著；当温度低于980 K时,大直径的空洞数目不再增加.

Phase Field Model of the Dynamics of Growth in Voids during Czochralski Silicon Crystal Growth

A phase field model of void dynamics during CZ silicon crystal growth,combined with the temperature field from finite element method(FEM),has been developed.This model could simulate the evolution of void`s shape and distribution,and the void dynamics at different initial defect concentrations.The simulation results showed that void dynamics followed four stages at different temperature intervals: incubation,nucleation,growth and static.Different from low initial vacancy concentration,void fraction and diameters increased evidently at high concentration.The number of voids whose diameter is over 10 nm has little fluctuation at the temperature to be lower than 980 K.