Humidity sensing properties of CNx film by RF magnetron sputtering system

Humidity sensing properties of carbon nitride (CNx), which is a new material for humidity sensors, have been investigated and a simple model for water molecular adsorption in carbon nitride surface has been suggested. Carbon nitride films were deposited on silicon substrate with meshed electrodes by reactive RF magnetron sputtering system. The film revealed not only good humidity-impedance characteristics but also relatively quick response to relative humidity changes. When water molecules attack the carbon nitride surface, the CN bonds break up and the released nitrogens and carbons form CHO and NHO bonds. It can be expected that CNx thin films can be used for Si-based micro-humidity sensors.