FE AU MULTILAYER GROWTH FRONTS - COMPARISON OF X-RAY DIFFUSE-SCATTERING RESULTS WITH ATOMIC-FORCE MICROSCOPY PROFILES/

The interfacial roughness morphology of sputtered Fe/Au multilayers wa s derived by combining the results from X-ray specular and non-specula r (diffuse) scattering. From the non-specular intensity collected by a two-dimensional image plate we determined the in-plane height-height correlation function [H-i(R)H-i(O)] and the growth correlation length as a function of feature size. From these parameters we determined bot h the static and dynamic roughness exponents alpha: and z, which agree with the Kardar-Parisi-Zhang (KPZ) model of surface growth. The heigh t difference function derived from the diffuse scattering is compared with several model functions that incorporate the asymptotic behavior of [H(R)(2)] for the cases of R --> O and R --> co. We show that only one particular function is appropriate. The evolution of the interfaci al slope is determined from the roughness exponents, and it is shown t hat it decreases as a function of time. This asymptotic smoothing is a nalyzed using the noiseless and stochastic KPZ equations. The noiseles s KPZ equation predicts that the growth front is composed of paraboloi ds, which increase in lateral size and coalesce. This result is suppor ted by an Atomic-force Microscopy measurement of the surface of one of the Fe/Au Multilayers. (C) 1998 Elsevier Science B.V. All rights rese rved.