Surface step bunching and crystal defects in InAlAs films grown by molecular beam epitaxy on (111)B InP substrates

The surface morphology and crystal structure of InAlAs films grown by molecular beam epitaxy on (111)B InP substrates misoriented 1° toward [2̄11] have been investigated. Combined plane view transmission electron microscopy and atomic force microscopy observations have revealed spectacular terracelike topographies, induced by surface step bunching during the growth. Furthermore, cross section transmission electron microscopy analysis has shown the presence of threading dislocations, related to the giant steps, as well as strain inhomogeneities attributed to composition modulation. We have also demonstrated the potential use of the giant steps for local deposition of InAs.