PECVD prepared SnO2 thin films for ethanol sensors

SnO2 thin films are elaborated by a PECVD process in a RF glow discharge reactor. Two kinds of as-deposited films have been studied; unbiased (diode reactor) and biased ones (triode reactor) according to their properties and their response to specific gases such as ethanol. Characterization of the films are carried out by different techniques: FTIR, AES, X-ray diffraction, AFM in order to explain the modifications generated by the bias voltage. The detection results show best sensitivities (S=Ra/Rs) for unbiased films to ethanol at 450°C (S=45 for 10 ppm).