Simulation of Frank-Read sources in silicon

Abstract

A simulation of dislocation sources in silicon is presented that has been developed in order to examine further how dislocation dynamics and multiplication govern the initial stage of plastic flow in diamond cubic crystals. The numerical method is adapted from an existing code by introducing specific dislocation properties deriving from the presence of strong Peierls forces. The influence of stress and temperature on the dynamics and configurations of Frank-Read sources are examined on {111} sections of model crystals of dimensions larger than 100 μm 2. Most of the results obtained can be qualitatively interpreted in terms of the various contributions to the effective stress on the dislocation segments and of the particular character of the stress vs velocity laws in silicon. The backstresses in the slip plane and in the cross-slip plane are investigated in some detail in the conditions of the upper yield point. These results aim at providing numerical inputs for the recent model on mechanical twinning in semiconductors proposed by Pirouz.