Nanosecond laser ablation of Si(111) under an aqueous medium

Nanosecond laser ablation of p-type Si(111) wafer is presented under an ambient, a water and a glycerin conditions. Effects of pulse energy, number of pulses and type of environment are systematically analyzed with an Optical Profilometer, a Scanning Electron Microscope and an Atomic Force Microscope. Obtained results are compared with Zemax*-EE simulations. Self-assembly nano-ripple formation has been observed in an ambient condition. However, these ripples and heat affected zone (HAZ) area disappeared in aqueous medium which enhances the quality of ablation. Moreover, no remarkable oxidation was obtained in ablation zone even in an ambient condition based on the SEM-EDX analysis. Ablation profiles and their depths for different environments are compared with false color technique. Although ablation diameters are comparable each other, their depths are small enough in aqueous medium to control depth profile of damaged area. According to our results, best ablation profiles (precise edges without HAZ) are achieved under an aqueous medium especially in glycerin conditions both in low and high pulse energy regime.