Roughness conformity during tungsten film growth: An<i>in situ</i>synchrotron x-ray scattering study

Abstract

The spatial and temporal evolution of the surface of a tungsten film deposited by magnetron sputtering is investigated in situ and in real time by an x-ray scattering technique. The evolution of roughness is described in terms of its power spectral density and derived from scattering measurements performed using synchrotron x-rays at the energy of $17.5\phantom{\rule{0.3em}{0ex}}\mathrm{keV}$. The data are analyzed in the frame of the first-order perturbation theory, which does not require any model of film growth and correlation function. The approach allows extracting quantitatively both the degree of conformity and the evolution of the in-plane characteristic length of the replication as a function of the growing film thickness.