Thermal modeling and experimental study of infrared nanosecond laser ablation of silicon

Nanosecond (ns) laser ablation of silicon has important applications in electronics, photovoltaics, and many other areas. However, most of the previous work is mainly focused on ultraviolet (UV) or visible ns lasers, and the investigation is very limited for infrared lasers (e.g., at 1064 nm), which have the advantage of much lower cost and external energy consumption. In this paper, a thermal model has been developed and experimentally verified for ablation of silicon by 200 ns and 1064 nm laser pulses. This kind of work has been rarely reported in literature. The model predictions agree reasonably well with experimental measurements. The investigation indicates that surface evaporation should be the dominant physical mechanism of material removal for laser silicon ablation under the studied conditions. It has also been found that the physical processes of multipulse laser-silicon interaction at 1064 nm may strongly depend on laser pulse number and repetition rate (the pulse-to-pulse temporal distance).