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

TL;DR

This study investigates nanosecond laser ablation of Si(111) in different environments, revealing that aqueous media, especially glycerin, improve ablation quality by reducing heat-affected zones and preventing ripple formation.

Contribution

It provides a systematic comparison of laser ablation in ambient, water, and glycerin environments, highlighting the benefits of aqueous media for precise silicon surface processing.

Findings

Aqueous media eliminate nano-ripples and HAZ, improving ablation quality.

Ablation depths are smaller in aqueous media, allowing better control.

Glycerin yields the best ablation profiles with precise edges.

Abstract

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.