Patterning-based investigation of the length-scale dependence of the surface evolution during multilayer epitaxial growth

We describe an investigation of the lateral length scale dependence of the evolution of topographical corrugations during multilayer molecular beam epitaxial growth in the GaAs/AlAs multilayer system. By patterning the substrate at series of well-defined spatial periods, we are able to study selectively the changes which occur as a function of lateral period over a wide range of corrugation amplitudes. A critical pattern period, which increases monotonically with thickness, separates an initial long spatial period regime where roughness is amplified, from a later, short spatial period regime in which the topography of the growing surface smoothes out.