Study on the densification of SiO2-TiO2 sol-gel films by laser irradiation

In order to study the application of laser direct writing technology in the area of thin film elements rapid fabrication,the densification of SiO2-TiO2 porous sol-gel films on SiO2/Si wafer was performed by means of a continuous fiber laser with the wavelength of 1.07μm.The effect of laser power density on the shrinkage of the film was investigated.The thresholds of laser power density and the change of thickness of films under different preheated temperatures were discussed.Finally,the mechanism of laser densification of the SiO2-TiO2 films was also analyzed.The experimental results demonstrate that the shrinkage of films increases with the laser power density.The thresholds of laser power density will increase with increasing temperature in the process of laser densification.The energy of induced laser beam is absorbed by Si substrate instead of Sol-Gel film.The mechanism of laser densification of the SiO2-TiO2 films is mainly based on the shrinkage of nanon-scale pore due to the energy transfer from Si wafers.