Mechanics of Shaped Crystal Growth from the Melt

该项目解决了在硅、砷化镓和磷化铟的立方、圆柱形晶体生长过程中位错的产生和增殖问题，这些晶体是通过Czochralski方法或液体封装- Czochralski方法从熔体中提取的。重点介绍了高温变形过程中热应力的计算。将研究三个主要影响：1)熔体与晶体之间固液界面的形状，对其控制可以大大降低所产生的热应力；2)晶体生长方向的各向异性，在一定的晶体各向异性下，选择适当的晶体各向异性可以使所产生的位错密度最小；3)利用高温非弹性本构定律，将位错密度作为内部变量，并考虑其微观组织演变，实现位错的产生和增殖。新的定性和定量的理解，重要的基本过程在半导体体单晶生长预计从这个项目；研究结果也与微电子工业具有技术相关性。

This project addresses the generation and multiplication of dislocations during the growth of cubic, cylindrical crystals of Silicon, Gallium Arsenide, and Indium Phosphide which are pulled from the melt by the Czochralski or the liquid-encapsulated- Czochralski method. Emphasis in on the computation of thermal stresses during high temperature deformation. Three major effects will be studied: 1)the shape of the solid-liquid interface between the melt and crystal, whose control may greatly reduce the resulting thermal stresses, 2)the crystalline anisotropy in relation to the direction of crystal growth, whose proper choice may minimize the resulting dislocation density for a given amount of crystalline anisotropy, and 3)dislocation generation and multiplication by using high temperature inelastic constitutive laws which treat the dislocation density as an internal variable and allow for its microstructural evolution. New qualitative and quantitative understanding of fundamental processes important to bulk single crystal growth in semiconductors is anticipated from this project; the results also have technological relevance to the microelectronics industry.