X-Ray Scattering Study of the Surface Morphology of Au(111) during Ar1 Ion Irradiation

Using real-time x-ray scattering to measure the surface morphology of Au(111) during sputter erosion with 500 eV Ar ions, we observe three distinct regimes: three-dimensional rough erosion at 20–60 ±C, quasi-layer-by-layer removal at 120–220 ±C, and step retraction above 270 ±C. Sputtering at 20–60 ±C leads to pattern formation with a characteristic spacing between features. The average separation l between features increases with time t, consistent with a power law l , t0.2760.02. The observations are consistent with the predictions of a continuum model for deposition which includes an EhrlichSchwoebel barrier to the interlayer diffusion of surface defects. [S0031-9007(98)06122-5]