4H-SiC Surface Modified by a Green Femtosecond Laser at Low Fluence

This study used a single femtosecond laser pulse with a wavelength of 515 nm to irradiate the 4H-SiC sample surface. The pulse energy was 1740-2110 nJ, and the effective fluence was around 1.27-1.54 J/cm2. The ablation threshold is 1.26 J/cm2. The surface morphology and the ablation depth were measured by scanning electron microscopy (SEM) and atomic force microscope (AFM). The ablation depth is around 12 nm. On the other hand, a simplified model with a two-temperature model and dynamic optical model was used to predict the ablation threshold. The simulation result shows that the ablation threshold is around 1.2 J/cm2, which is matched the experimental results.