Dislocation dynamics in the plastic deformation of silicon crystals. II. Theoretical analysis of experimental results

Abstract

Experimental results on the deformation of silicon crystals reported in a foregoing paper are discussed on the basis of a model and a hypothesis so far proposed. The dependence of the upper and the lower yield stresses on the temperature and the strain‐rate can be described reasonably well by the model of Haasen et al. Origins for some discrepancies between the results of the model and the experiments are discussed. The behaviour of the effective stress in the deformation stage after the middle of stage 0 is well described by the hypothesis of the steady state of deformation proposed by Sumino. The relation between the condition for the lower yield point and that for the steady state of deformation is discussed.

Deformation behavior of silicon

“…[42] However, the calculated magnitudes where K is a constant. We assume N ϭ N t in the following, of the lower yield stress are systematically lower than the namely, that all dislocations in the crystal are in motion.…”

An overview of plasticity of Si crystals governed by dislocation motion

“…In the temperature range above the knee at around 400˚C, the macroscopic deformation of various semiconductor crystals, including Si, is rate-controlled by the collective motion of dislocations known as the Alexander-Haasen-Sumino model [1,2,33,57,58]. The flow stress  a for deformation of a crystal is the stress needed to move dislocations within the crystal at a certain velocity that is determined by the strain rate and the density of dislocations in motion.…”

Influence of grain boundaries intentionally induced between seed plates on the defect generation in quasi‐mono‐crystalline silicon ingots

“…It is assumed that some dislocations are formed directly during growth at the solid-liquid interface to minimize the grain boundary energy [9]. In a second step these dislocations can act as nucleation sites for further dislocation formation and multiplication according to the Alexander-Haasen-Sumino model [12,13]. Especially in experiment GB2 (figure 4) the dislocation movement towards the crystal volume can be observed.…”