Influence of the substrate on the overall sensor impedance of planar H2 sensors involving TiO2–SnO2 interfaces
- Chair of Metrology and Control Engineering, Universität Bayreuth, Bayreuth, Germany
Abstract. To date, very little has been written about the influence of the substrate layer on the overall sensor impedance of single- and multilayer planar sensors (e.g., metal-oxide sensors). However, the substrate is an elementary part of the sensor element. Through the selection of a substrate, the sensor performance can be manipulated. The current contribution reports on the substrate influence in multilayer metal-oxide chemical sensors. Measurements of the impedance are used to discuss the sensor performance with quartz substrates, (laboratory) glass substrates and substrates covered by silicon-dioxide insulating layers. Numerical experiments based on previous measurement results show that inexpensive glass substrates contribute up to 97% to the overall sensor responses. With an isolating layer of 200 nm SiO2, the glass substrate contribution is reduced to about 25%.