Modeling and Optimization of Edge Dislocation Stressors

Dislocation stressors in the source and drain build the tensile stress field in the channel of nMOSFET. An analytic model of the strain/stress field induced by the edge dislocation is presented. The model is used for stress optimization of the dislocation stressors in the nMOSFET channel. The accuracy of the model is similar to that of the finite element simulation. The closed-form solution provides a physical insight into the dislocation stressor. The analytic solution shows that shallower dislocations generate a larger tensile stress at the edge of the channel near the virtual source. For a given dislocation depth, an optimal distance of the dislocation core from the edge is required to generate the maximum tensile stress at the channel edge.