Pulsed laser deposition of silicon dioxide thin films with silicone targets for fabricating waveguide devices

摘要

Silicon dioxide (SiO_2) thin films were deposited at room temperature by 193-nm ArF excimer laser ablation of silicone in oxygen atmosphere. Only the side chains (CH_3) of the target were photo-dissociated during ablation to deposit Si-O bonds on a substrate in high laser fluence at about 10 J/cm~2. Oxygen gas worked to oxidize the Si-O bonds ejected from the target to form SiO_2 thin films at the gas pressure of 4.4 * 10~(-2) Torr, in addition to reducing the isolated carbon mined into the films. We also found that the deposition rate could control refractive index of the films. The refractive index of the film deposited at 0.05 nm/pulse is greater than that of the film at 0.1 nm/pulse. Thus, a 0.2-μ m-thick SiO_2 cladding film deposited at 0.1 nm/pulse was firstly formed on the whole surface of a 100-μ m-thick polyester film, and then a 0.6 μ m-thick SiO_2 core film at 0.05 nm/pulse was fabricated in a line on the sample. The sample functioned as a waveguide device for a 633-nm line of He-Ne laser.