Multilayer SiC/C Thin Film Coating on Fiber Tip for Raman Probe Application

A novel technique in the fabrication of an optical filter that is made up of multilayer thin film is introduced in this study. Multiple layers of silicon carbide and carbon with high and low refractive index materials respectively will be deposited alternatively with a various thickness on a glass substrate by radio frequency magnetron sputtering of 99% purity of silicon carbide as the target. The variation of structure and optical properties of the films are studied by using X-ray reflectivity (XRR), Raman scattering spectroscopy, and UV–vis-NIR spectroscopy until it reached the desired results and meet the specification as Raman optical filter. The thin film is then placed on a multimode fiber tip as Raman edge filter. Raman fingerprint of specific alcohol (ethanol) obtained is tested using a fabricated filter with the standard spectrum. The preliminary result of SiC thin film fabrication for 30, 60 and 90 minutes by sputtering process showed rate of deposition obtained is 3.17nm/min. The results demonstrate that the optical properties of silicon carbide thin film can be monitored by modifying the condition of silicon carbide and carbon deposition. (paper)