Improvement of Gas Sensitivity by Lowering Carrier Density and Thinning Film Thickness of SnO₂ Gas Sensor

Abstract

In this study, we investigated dependence of carrier density and film thickness on H2 gas sensitivity using tin dioxide (SnO2) films deposited by RF magnetron sputtering. Our aim is fabricating a gas sensor that can detect ppb-level gas concentrations for health care applications. It had been reported that lower carrier density and thinner film thickness contributed improving sensitivity of a gas sensor. We balanced lower carrier density and thinner film thickness by using a sapphire substrate for depositing tin oxide in addition to annealing treatment to tin oxide films. In the result, we clarified that thinning film thickness of tin dioxide affected on improving its gas sensitivity more significantly than lowering carrier density.