Temporal evolution of dot patterns during ion sputtering

The temporal evolution of the morphology of GaSb surfaces induced by ion bombardment is investigated. The erosion process with normal incident argon ions forms a regular dot pattern that shows an increase of ordering among the dots with increasing sputtering time. The pattern stabilizes to a highly uniform, hexagonally ordered dot pattern for very long times. The degree of ordering is determined by quantitative analysis of the surface roughness and the power spectral density of the surface pattern using atomic force microscopy. A comparison of the experimental results with numerical integrations of the unstabilized Kuramoto-Sivashinsky equation shows that this equation cannot reproduce essential details of the experimental pattern observed.