Film quality effects associated with formation of misfit dislocations at semiconductor interfaces

The influence of the interface orientation on the strain state and structure properties of epitaxial layers is theoretically investigated for semiconductor films grown on (001) misoriented substrates. The analysis shows that for two intersected MD arrays, the film energy strongly depends on the type of the screw component of their Burgers vector. The energy is much lower if for both mutually perpendicular MD arrays the components are left-screw or right-screw. Identification of these components for 60° misfit dislocation arrays lying in a (001) interface may explain some experimental results of deteriorated epitaxial film structures. If the plastic relaxation process occurs in quasi-equilibrium; the whole multitude of vicinal (001) orientations can be classified into two types: orientations of type 1, when the conditions for threading dislocation formation are present, but the long-range stress field does not appear, and orientations of type 2, when the probability of threading dislocation formation is small, but the field is present.