Comparative study of large area pulsed laser deposited metal oxides for gas sensors applications

Large area pulsed laser deposition was used to deposit different metal oxide thin films on wafer-level aiming to find materials for miniaturized gas sensors. Radial dependency of thickness and electrical resistance was investigated by spectroscopic ellipsometry and four-point-probe measurements to reveal film homogeneity over the wafer. An innovative two-side trenched silicon shadow mask was used for layer structuring. In gas measurements the resistive response of the layers to gas atmospheres was investigated and compared. Carbon monoxide in concentrations of several ppm was used as a first model gas for emissions from test fires. Indium oxide and tin oxide showed good sensitivity and short response time.