Influence of SiC thin films thickness on the electrical properties of Pd/SiC thin films for hydrogen gas sensor

Abstract In this work, the effect of thickness of SiC thin film on hydrogen sensing property of Pd/SiC (Pd-capped SiC) thin films has been investigated. Pd/SiC thin films have been grown on Si (100) substrate by RF magnetron sputtering at 400 °C with varying the deposition time from 1 h to 3 h. The thickness of the SiC films and Pd capping layer has been measured by FE-SEM cross section views and XPS, respectively. The growth of Pd/SiC thin films is confirmed by the XRD and Raman spectroscopy. The surface morphology of Pd/SiC films were studied by atomic force microscopy (AFM) and all the deposited films are found to be dense, uniformly distributed with spherically shaped surface particles. The change in electrical resistance is found completely reversible at 250 °C temperature during hydrogenation/dehydrogenation process for Pd/SiC thin film sensor deposited for 1 h with its smaller thickness. The Pd/SiC thin film sensor provides excellent sensitivity with high response (17%) and response time (18 s) towards hydrogen gas (2 bar) at working temperature of 250 °C.