SiO2 films fabricated by F2 laser-induced chemical deposition using silicone rubber

Silicon dioxide (SiO2) films were selectively fabricated on a Si substrate at room temperature by illuminating both the silicone rubber target and the substrate with an F2 laser (157 nm). The laser fluence was much less than the ablation threshold. Absorption due to absorbed water (H2O) and hydrogen-bonded silanol (SiOH) groups were observed in addition to absorption due to Si-O-Si stretching mode in the Fourier transform infrared spectroscopy (FT-IR) spectra of the films. The illumination with higher laser fluence caused an increase of Si-O-Si/OH peak ratio in the FT-IR spectra, a decrease of etching rate in hydrofluoric acid (HF) solution, and an increase in the refractive index close to the value of a thermal SiO2 film. These results indicate that the quality of the grown SiO2 films was improved. The high photon energy of F2 laser induced photodissociation of main chains and side chains of silicone and oxygen (O2), and bonds between the ejected gaseous molecules including Si and O(1D) to form SiO2 films.