The problem of generation of L-shape misfit dislocations (MDs) is investigated for (001) heterosystems with diamond and sphalerite crystal structures. These 60 degrees MDs can be formed by modified Frank-Read dislocation sources as well as by Hagen-Strunk ones. The analysis shows that perpendicular dislocation lines included in L-shape MDs have different types of screw dislocation components (namely, left-screw and right-screw ones). As a result, the stress-releasing process tends to slow preventing further generation of L-shape dislocations and annihilation of threading dislocations (TDs). To minimize density of TDs and to form equilibrium plane MD networks at the final stage of stresses relaxation process, it is necessary to generate mutually perpendicular MD arrays with the same types of screw dislocation components.