Simulation of point defect diffusion in structures with local elastic stresses

TL;DR

This paper uses computer simulations to study how local elastic stresses influence the diffusion and segregation of point defects in semiconductors, especially after ion implantation.

Contribution

It introduces a model for defect diffusion considering local elastic stresses and analyzes their effects on defect distribution and segregation.

Findings

Elastic stresses cause defect segregation or depletion within the strained layer.

Local elastic stresses do not significantly alter defect distribution outside the stressed region.

The model shows defect behavior depends on drift direction relative to the stress field.

Abstract

The stress-mediated diffusion of nonequilibrium point defects from the surface to the bulk of the semiconductor is investigated by computer simulation. It is supposed that point defects are generated in the surface region by ion implantation and during diffusion pass over the local region of elastic stresses because the average defect migration length is greater than the thickness and depth of the strained layer. Within the strained layer point defect segregation or heavily defect depletion occur if defect drift under stresses is directed respectively in or out of the layer. On the other hand, the calculations show that, in contrast to the case of local defect sink, the local region of elastic stresses practically does not change the distribution of defects beyond this region if there is no generation/absorption of point defects within the strained layer.