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 of material removed per pulse) is observed to decrease with residual film thickness and increase with laser fluence. The fluence threshold for the onset of ablation is shown to depend inversely on the initial film thickness. This behaviour is explained in terms of a thermal removal mechanism in which the thermal properties of the substrate play a vital role in regulating the film ablation characteristics.