Deformation behavior of silicon

Abstract

Dynamic processes of individual dislocations in Si, such as generation, motion, and multiplication, are reviewed on the basis of direct observations by means of X-ray topography and transmission electron microscopy. The characteristics in the reaction of oxygen impurities with dislocations are clarified by real time observations with these techniques. Immobilization of dislocations due to the reaction is demonstrated. Stress-strain behavior of Si in the yield deformation is described in detail. It is sensitive to the deformation temperature, strain rate, and also to the density of dislocations initially contained in the crystal. Though the yield behavior of Si crystals free from dislocations is not influenced by oxygen impurities contained, that of dislocated crystals is affected significantly by these impurities. All of these characteristics in the yield deformation of Si are shown to be successfully described with a model that takes into account the dynamic processes of individual dislocations revealed by the direct observations.