New Approach in Equilibrium Theory for Strained Layer Relaxation

We present a new approach in equilibrium theory for strain relaxation in metastable heteroepitaxial semiconductor structures, one which includes the elastic interaction between straight misfit dislocations. The free-surface boundary conditions are satisfied by placing an "image dislocation" outside the crystal in such a manner that its stress field cancels that of the real misfit dislocation at the surface. This image method provides an equilibrium theory which correctly predicts critical strained layer thicknesses and completely describes the strain relief via plastic flow in lattice mismatched epilayers.