Thermal stress analysis of GSO bulk single crystal

Abstract

A three-dimensional finite element computer program was developed to deal with the thermal stress analysis of a GSO bulk single crystal during Czochralski growth. A GSO single crystal is monoclinic, and has strong anisotropy in the elastic constants and thermal expansion coefficients, so that three-dimensional analysis is required for the exact calculation of thermal stress of a GSO single crystal. A tensor transformation technique was used to obtain the components of elastic constant matrix and thermal strain or thermal expansion coefficient vector corresponding to an arbitrary pulling direction. Using this computer program, thermal stress analyses of a GSO bulk single crystal were performed for various pulling directions in order to examine the relation between the magnitude and distribution of thermal stress in the bulk single crystal and the pulling directions. The b-axis pulling of a GSO bulk single crystal was proposed from the viewpoint of minimizing thermal stress during growth process.