The in-plane length scale of the conformal interface roughness as a function of bilayer repeat number in Co/Pd multilayers

Abstract

Grazing incidence small angle x-ray scattering has been used to probe the in-plane length scale and scaling behaviour of the conformal interface roughness of sputtered Co/Pd multilayers. Scaling was seen in the intensity distribution through the Bragg sheets for large out-of-plane wavevectors. The scaling exponent showed power law variation with multilayer repeat number, the extreme values being close to those predicted by the Kardar–Parisi–Zhang and Tang–Alexander–Bruinsma models of film growth. The wavevector at which scaling broke down increased linearly with repeat number. A power law increase as a function of bilayer repeat number was found in the in-plane correlation length defined by fitting the scattering in the incidence plane to the Sinha model. Both approaches showed that the multilayer interfaces tended towards a two-dimensional character as the number of repeats increased.