Techniques to Predict Dislocation Generation During Growth of Silicon Ribbon

This paper describes the numerical techniques that are used to predict stresses, strains, dislocation densities, and buckling during the growth of flat plate silicon. High quality silicon ribbon would be an ideal starting material for manufacturing solar cells for electrical power generation. The techniques developed are uniquely related to the material model that is used which is a generalization of the silicon model reported by Hassen in Germany, Sumino in Japan and their co-workers. The novelty of the model is that it accounts for a changing dislocation density and through this, the plastic strain rate also changes with the dislocation density. The rate of dislocation generation depends on the stresses, temperature as well as the existing dislocation density. The numerical techniques that are discussed incorporate this novel material model in the analysis of the silicon ribbon growing process. This approach requires that the stresses and dislocation density due to a complex thermal field be determined. The details of these techniques are the main feature of this paper.