Co-GISAXS as a New Technique to Investigate Surface Growth Dynamics

TL;DR

This paper introduces Co-GISAXS, a novel X-ray scattering technique, to quantitatively analyze nanoscale surface dynamics during thin film growth, revealing complex behavior and dynamical scaling in sputter-deposited films.

Contribution

The paper presents Co-GISAXS as a new experimental method for investigating surface dynamics in thin films, providing detailed quantitative insights.

Findings

Surface roughening reaches a steady state during growth.

Correlation functions exhibit compressed exponential behavior.

Dynamics follow power law scaling.

Abstract

Detailed quantitative measurement of surface dynamics during thin film growth is a major experimental challenge. Here X-ray Photon Correlation Spectroscopy with coherent hard X-rays is used in a Grazing-Incidence Small-Angle X-ray Scattering (i.e. Co-GISAXS) geometry as a new tool to investigate nanoscale surface dynamics during sputter deposition of a-Si and a-WSi$_2$ thin films. For both films, kinetic roughening during surface growth reaches a dynamic steady state at late times in which the intensity autocorrelation function $g_2$(q,t) becomes stationary. The $g_2$(q,t) functions exhibit compressed exponential behavior at all wavenumbers studied. The overall dynamics are complex, but the most surface sensitive sections of the structure factor and correlation time exhibit power law behaviors consistent with dynamical scaling.