The Simulation of Thermal Stress Field for Polysilicon Crystal in Different Shapes of Crucible

Abstract

The thermal stress field in the polysilicon was simulated and comparatively analyzed at different shapes of crucibes which have different types of a flat, a inverted-conical and concave bottom by COMSOL Multiphysics version 4.3a. The results indicated that: within the flat-bottomed crucible ,the isotherm in the crystal was slightly convex and the area of the maximum thermal stress was distributed in the bottom of the crystal edge and near the top of crystal edge; within the inverted-cone crucible, the isotherm in the crystal was straight and the area of the maximum thermal stress was only distributed in the bottom of the crystal edge; within the bottom of the concave crucible, the isotherm in the crystal was slightly concave and the area of the maximum thermal stress distributed in the bottom of the crystal edge was larger than that of the crystal within the first two kinds of crucibles. To sum up, the inverted-cone crucibe was beneficial to reduce the thermal stress distribution in the polysilicon which could provide theoretical guidance for improving the production process of the polysilicon.