Strain-driven transition from stepped interfaces to regularly spaced macrosteps in (GaIn)As/Ga(PAs) symmetrically strained superlattices

We investigate the morphological transition from a steplike interface modul ation to a highly periodic lateral thickness modulation that occurs on symm etrically strained (GaIn)As/GaAs/Ga(PAs)/GaAs superlattices grown by metal- organic vapor phase epitaxy on miscut (001)GaAs substrate. The combination of x-ray reciprocal-space mapping, around the (004) as well as the (200) an d (020) reciprocal-lattice points, and transmission electron microscopy all owed us to monitor and analyze accurately the structural periodicities and ordering of heterointerfaces and to relate them to the elastic strain field . The laterally ordered macrosteps on the growth surface are investigated a nd discussed as a function of the strain misfit between epitaxial layer and substrate. Within this purpose, the complementary information obtained by grazing-incidence x-ray diffraction, by looking at different reciprocal-lat tice points, is discussed in relationship to the effects of strain and morp hological modulation of the interfaces in the process of macrostep formatio n.