1998 Volume 41 Issue 4 Pages 488-494
A three-dimensional finite element computer code was developed to deal with a thermal stress analysis of a gadolinium orthosilicate(Gd2SiO5, hereafter abbreviated as GSO), a monoclinic single crystal, during Czochralski growth process. The GSO single crystal has strong anisotropy in the elastic constants and the thermal expansion coefficients, so a three-dimensional analysis is required for the exact calculation of thermal stress. A tensor transformation technique was used to obtain the components of the elastic constant matrix and the thermal strain or the thermal expansion coefficient vector corresponding to an arbitrary pulling direction. Using this computer code, thermal stress analyses of the 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 the GSO bulk single crystal was proposed from the viewpoint of minimizing the thermal stress during the growth process.