Capacitive sensor arrays with controllable deposition of the sensing polymer area for VOCs applications: Design and measurement considerations

InterDigitated Capacitive (IDC) sensor arrays are fabricated with conventional microelectronics-micromachining technologies on quartz substrates. After the IDC fabrication, a polymeric well is patterned around each IDC to precisely define the sensing area and thus deposit coatings of various polymers, by drop casting, in a reproducible and controlled manner. The performance of the coated IDC array is evaluated in terms of IDC critical dimension, measurement frequency and for two analytes and guidelines for improved sensing performance are proposed. Through careful selection of the polymeric coatings in conjunction with suitable signal processing, discrimination of VOCs is possible.