Parylene-C encapsulated TiO2/Glycerol UV sensor implemented on silicon chip using low temperature process

This study presents a novel approach to implement Ultraviolet (UV) sensor using low temperature process. The UV-sensitive TiO₂/Glycerol is embedded inside a cavity on silicon chip and then encapsulated by CVD (chemical vapor deposition) parylene C film. In addition, the percentage weight of TiO₂ in TiO₂/Glycerol can be easily changed to improve the performance of UV sensor. The characteristics of photo-response measured from the presented photo sensor of 0~30 wt% TiO₂. Typical measurements show the photo-dark current ratio ranging 2.04-5.70, response time ranging 40-48 sec, and recovery time: ranging 5-10 sec. Moreover, the UV sensor with 20 wt% TiO₂ content shows a higher UV sensitivity. The performances of presented sensor with various electrode gap designs (1581-335μm) under 20wt % TiO₂ have also been characterized. Typical measurements show the photo-dark current ratio ranging 11.4-5.85, response time ranging 19-23 sec, and recovery time: ranging 1.5-6 sec. Moreover, the UV sensor of with 335 μm gap design show a higher UV sensitivity.