XECL LASER-ABLATION OF THIN-FILM ZNS

XeCl laser ablation of films of ZnS, with 200-600 nm thickness, on Si substrates has been studied at laser fluences lower than that required to damage the substrate material. The ZnS film ablation rate (depth o f material removed per pulse) is observed to decrease with residual fi lm thickness and increase with laser fluence. The fluence threshold fo r the onset of ablation is shown to depend inversely on the initial fi lm thickness. This behaviour is explained in terms of a thermal remova l mechanism in which the thermal properties of the substrate play a vi tal role in regulating the film ablation characteristics.