ON THE GENERATION OF MISFIT DISLOCATIONS

Experimental measurements in epitaxial semiconductor deposits of the critical thickness above which misfit dislocations are generated may differ substantially from values calculated from early models that are successful for metallic deposits. The early models of misfit dislocation generation based on a glide mechanism for threading dislocation have been modified to include frictional forces on threading dislocations. The modified model can account for the critical thickness in both metal as well as semiconductor expitaxial deposits. It results in a residual stress that is not relaxed even at large deposit thicknesses. The influence of the frictional forces is diminshed at large misfits.