Investigation of the formation of nanostructures on silicon thin films by excimer laser irradiation

We present a theoretical study and experimental results on the formation of conical nano-tips on silicon thin films as a result of single-pulse excimer laser irradiation. The fabricated structures have heights of about 1 μm and apical radii of curvature of several tens of nanometers. An individual cone is formed when a mono-crystalline silicon film on an insulator substrate is irradiated in air environment with a single 25ns pulse from a KrF excimer laser, homogenized and shaped to a circular spot with diameter of several micrometers. Atomic force microscopy was used to study these structures. A simplified analytical model for the formation of these structures is proposed. We also present computer simulations of heat transfer in Si films that results from irradiation with a single laser pulse, shaped to a circular spot