CROSSHATCHED SURFACE-MORPHOLOGY IN STRAINED III-V SEMICONDUCTOR-FILMS

The correlation between the surface crosshatched morphology and the interfacial misfit dislocations in strained III-V semiconductor heteroepitaxy has been studied. The surface pattern is clearly seen on samples grown at high temperature (520°C) and those with small lattice-mismatched (f<2%) systems. A poorly defined crosshatched morphology was found on layers grown at relatively low temperature (400°C). As the lattice mismatch of the strained layer becomes larger than 2%, a roughly textured surface morphology is commonly observed in place of actual cross-hatching. Few threading dislocations are observed in the strained layer when the crosshatched pattern develops. It is also noted that the surface crosshatched pattern develops after the majority of the interfacial misfit dislocations are generated. The result suggests that the surface crosshatch pattern is directly related to the generation of interfacial misfit dislocations through glide processes.