Influence of the misfit-dislocation screw component on the formation of threading dislocations in semiconductor heterostructures

In heterostructures with the (001) interface and diamond and sphalerite crystal lattices, the total relief of mismatch stresses by introducing two mutually perpendicular arrays of 60° misfit dislocations (MDs) was shown to be possible only if their screw components were of the same type. In the opposite case, it was necessary to introduce additional MD arrays that increased the probability of formation of threading dislocations in an epitaxial film. When the process is nonoptimal and two mutually perpendicular arrays are introduced with opposite types of screw components, excess energy of long-range shear stresses is accumulated. Examples of nonoptimal introduction of misfit dislocations are the operation of the Frank-Read and Hagen-Strunk modified dislocation sources. The relaxation process was simulated and investigated experimentally.