Plasmapolymerized silicon organic thin films from HMDSN for capacitive humidity sensors

Capacitive humidity sensors were fabricated employing a plasmapolymerized hexamethyldisilazane (HMDSN) thin film layer as the moisture sensitive material. The sensor design comprises interdigital electrodes, the plasmapolymer, and a porous top electrode. A humidity sensor with a simple structure and small dimensions (6 mm2) has been developed and characterized exhibiting a response time below 1 min, good reversibility, and a high sensitivity. The variation of the plasmapolymerization parameter resulted in different humidity sensing properties which could be correlated to the results of the film analysis by FTIR, contact angle measurements, and SEM photography.