Interface roughness of InAs/AlSb superlattices investigated by x-ray scattering

InAs/AlSb short period superlattices grown either with AlAs-like or with InSb-like interfaces are investigated by grazing incidence x-ray scattering and high resolution diffractometry. The superlattices are grown on a relaxed AlSb buffer layer. It is shown that the two possible stackings of layers in the superlattices resulting in a different degree of lattice relaxation lead also to a different height of interface roughness. The lateral and vertical correlation lengths of the roughness decrease with increasing relaxation of the superlattice. The vertical correlation length corresponds to an almost complete correlation of different interfaces in the case of the nearly perfect superlattice with InSb-like interfaces. (C) 1996 American Institute of Physics.