Simulation of Transient Glide of a Threading Dislocation in an Embedded Strained Expitaxial Layer
Abstract
The material configuration is a thin strained layer embedded between two relatively thick, unstrained layers. The interfaces between the strained layer and the unstrained layers are assumed to be epitaxial, and the strain in the layer is assumed to arise from a mismatch in lattice parameters between the strained layer material and the surrounding material. The crystalline materials are assumed to have cubic symmetry, oriented so that (001) direction is normal to the interfaces. Initially, a long straight 60 deg dislocation exits on a (111) plane, extending from one otherwise strain-free region, through the strained layer, and into the other strain-free region. The process of glide of this dislocation is modeled under the action of the stress associated with the mismatch strain in the layer. The shape of the dislocation during glide is approximated by a continuous piecewise linear curve, and the location of the vertices of this curve are viewed as generalized coordinates of the system. A corresponding generalized force is defined at each node as the variation in total energy of the system due to variation in position of that node. A kinetic law of motion, suitable for thermally activated glide of the dislocation, is then cast into a form involving the nodal velocities and the corresponding generalized forces. The governing equations have been integrated numerically for material parameters representative of the GeSi/SI(001) strained layer systems.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1990
- Accession Number
- ADA226965
Entities
People
- Allan Bower
- Jean-claude Ramirez
- Lambert Ben Freund
Organizations
- Brown University