Comparative study on laser cleaning SiO2 particle on SrTiO3 and Si surfaces

In this paper, we perform a comparative study, both experimentally and theoretically, on the dry laser cleaning SiO2 particles on the surface of SrTiO3 (STO) and Si single crystal substrates. Firstly, the dependences of the cleaning efficiency on the laser energy density, the pulse number, and the size of SiO2 particles was investigated experimentally. It is found that the laser cleaning threshold decreases with the increase of SiO2 particle size. Furthermore, for the same size of SiO2 particles, the laser cleaning threshold of the STO surface is larger than that of Si. Then, based on the analysis of the interactions among the light field, the particles, and the substrate material, a corrected thermal expansion model with a quantified field enhancement effect was proposed, which provides a good simulation of the dependence of the laser cleaning threshold on the particle size and the substrate. These results further deepen our understanding of the laser dry cleaning, particularly the cleaning process on the oxide surface.