Synthesis and Characterization of Carbon Nitride Films for Micro Humidity Sensors

Nano-structured carbon nitride (CN(x)) films were synthesized by a reactive RF magnetron sputtering system with a DC bias under various deposition conditions, and their physical and electrical properties were investigated with a view to using them for micro humidity sensors. The FTIR spectra of the deposited films showed a C=N stretching band in the range of 1600∼1700 cm(-1), depending on the amount of nitrogen incorporation. The carbon nitride films deposited on the Si substrate had a nano-structured surface morphology with a grain size of about 20 nm, and their deposition rate was 1.5 μm/hr. The synthesized films had a high electrical resistivity in the range of 10(8) to 10(9) Ω·cm, depending on the deposition conditions. The micro humidity sensors showed a good linearity and low hysteresis between 5 ∼ 95 %RH.