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

摘要

An approach is developed for understanding the cross-hatch morphology in lattice mismatched heteroepitaxial film growth. It is demonstrated that both strain relaxation associated with misfit dislocation formation and subsequent step elimination (e.g. by step-flow growth) are responsible for the appearance of nanoscopic surface height undulations (0.1 - 10 nm) on a mesoscopic (-100 nm) lateral scale. The results of Monte Carlo simulations for dislocation-assisted strain relaxation and subsequent film growth predict the development of cross-hatch patterns with a characteristic surface undulation magnitude -so A in an approximately 70% strain relaxed In{sub}0.25Ga{sub}0.75As layers. The model is supported by atomic force microscopy (AFM) observations of cross-hatch morphology in the same composition samples grown well beyond the critical thickness for misfit dislocation generation.