Nanosecond laser pulses-induced surface microstructures on silicon

The surface spike microstructures are formed by Nd:YAG nanosecond laser pulses irradiating single crystal silicon wafers with energy densities within the ablation regime, in SF6 or air atmosphere. All the tops of the spikes created in SF6 atmosphere have small spheres, there are still the secondary tips on some spikes. There is granular material on the top and the edge of the spikes induced by nanosecond laser pulses in air atmosphere, which is formed by solidification of the droplets. The microstructures formed in air are different from the slender whiskerlike structures created by excimer laser and also different from the conical microstructures with dendritic nanostructures formed under femtosecond laser irradiation. The experimental results suggest that both the l