Development of cross-hatch morphology during growth of lattice mismatched layers

An approach for understanding the cross-hatch morphology in lattice mismatched heteroepitaxial film growth is developed. It is argued that both strain relaxation associated with misfit dislocation formation and lateral surface step flow are required for the appearance of mesoscopic scale surface undulations during layer growth. The results of Monte Carlo simulations for dislocation assisted strain relaxation and consequent film growth predict the development of cross-hatch patterns with a characteristic surface undulation magnitude similar to 50 Angstrom in an approximately 70% relaxed In0.25Ga0.75As layers. This is supported by atomic force microscopy observations of cross-hatch morphology in the same composition samples grown well beyond the critical thickness for misfit dislocation formation. (C) 2000 American Institute of Physics. [S0003- 6951(00)05049-X].