Anodic aluminum oxide-based capacitive humidity sensor integrated with micro-heater

摘要

AAO(Anodic Aluminum Oxide) film is fabricated as a sensing material for capacitive humidity sensors. Since AAO films have a lot of nano-size pores, many water vapors can be absorbed. As a porous layer thickness increases, sensor increases sensitivity as well as hysteresis. Rectangular spiral-shaped and interdigitated type are designed and fabricated as electrode types. Performance of the rectangular spiral-shaped type are compared with that of the interdigitated type. A micro heater is also integrated to evaporate condensed water vapors and contaminants. Linearity and reliability are improved by the heater and amount of hysteresis is reduced.