Consequences of misfit dislocation strain fields

This is the volume average tensile stress. As a representative numerical value of (Tave, suppose that 7 = IJ/m and that islands impinge when R = 80 nm. This implies that Tave = 25 MPa. The physical effect described here is believed to account for the increase in tensile stress observed for films during the early stages of deposition, as described in Section 1.8.3. 

Consider a uniformly strained film of thickness h that is epitaxially bonded to a relatively thick substrate which has essentially the same elastic properties as the film. Before any strain-relieving dislocations are formed in the 

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