KINETIC ROUGHENING OF QUENCHED XENON FILMS

Ralf K. Heilmann, Robert M. Suter, Department of Physics, Carnegie Mellon University, Pittsburgh, PA.
MRS Fall Meeting 1995

We investigate the growth of quenched Xe films formed by deposition onto a cold (16.5 - 35 Kelvin) SiO2/Si substrate. In-situ measurements of specular and diffuse x-ray reflectivity and diffraction line shapes are performed with a position sensitive detector. We determine the surface roughness, degree of conformality, in-plane correlations, and crystallinity as a function of Xe film thickness, substrate temperature, and annealing time in order to test for dynamic scaling behavior. Deposition of polycrystalline films with random crystallite orientations is achieved through heating of a grafoil sheet that is enclosed in the sample cell and has previously been covered with bulk Xenon to saturation pressure at 125 Kelvin. At 16 Kelvin the films are sufficiently quenched to be stable over several days, while at 25 Kelvin annealing takes place. Differing atomic mobilities at different temperatures might lead to contrasting scaling behavior. The well characterized substrate remains unchanged under repeated film deposition and desorption and therefore allows a systematic comparison of different film thicknesses.