Dislocation slip mechanism and prediction method during the ultra-precision grinding process of monocrystalline silicon

Abstract

Prediction of dislocation depth during ultra-precision grinding of monocrystalline silicon is a major challenge. To provide atomistic perspective, a single grain scratching molecular dynamics (MD) model of monocrystalline silicon is established to analyze the initiation and slip mechanism of dislocation. The simulation results show that the initiation of dislocations depends on the normal scratching force, and the dislocation length decreases with the decrease of scratching force and the increase of scratching velocity. Besides, the active slip system was identified by calculating Schmid factor, and the slip stress τ(111)[110],p (i.e. Peierls stress) of 2 GPa for ±1/2[110] dislocation on (1 1‾ 1) plane was obtained. Furthermore, a prediction model for dislocation depth was established based on the analysis of shear stress τ(111)[110]. Finally, a set of nano-scratch experiments were carried out, and the depth and slip direction of dislocation that close to the predicted were obtained by TEM method. This study provides a new method for predicting and controlling dislocation damage of monocrystalline silicon during ultra-precision grinding.