Forces between cavities and dislocations and their influence on semiconductor microstructures

An approximate continuum method for computing the energy of interaction between cavities and strain fields in complex configurations is described and tested by comparison with results for simple, exactly solvable cases. The method is then used to examine semiquantitatively the effective forces between cavities and screw and edge dislocations, taking into account the effects of surface tension and pressurized gas within the cavity. The discussion encompasses not only local interactions involving individual cavities, but also the combined forces acting upon dislocations in the vicinity of multiple cavities and simultaneously within range of external-surface image forces. The results are used to interpret a range of observed microstructures in semiconductors and to assess the possible exploitation of cavity-dislocation binding for dislocation control in Si-Ge heteroepitaxial structures. (C) 1999 American Institute of Physics. [S0021-8979(99)05518-8].