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 degrees toward <[(2)over bar 11]> have been investigated. Combined plane view transmission electron microscopy and atomic force microscopy observati ons have revealed spectacular terracelike topographies, induced by sur face step bunching during the growth. Furthermore, cross section trans mission electron microscopy analysis has shown the presence of threadi ng dislocations, related to the giant steps, as well as strain inhomog eneities attributed to composition modulation. We have also demonstrat ed the potential use of the giant steps for local deposition of InAs. (C) 1997 American Institute of Physics.