A resistive gas sensor with elimination and utilization of parasitic electric fields

Resistive gas sensors on silicon substrates consist of a stack of several t hin layers. Therefore, high electric fields result between the buried heate r and the near sensitive layer and its contacts. These fields pervade the t hin sensitive layer and affect the sensor response. This paper presents a s pecial sensor substrate which was developed to control this cross effect. E lectric fields across the sensing layer can be avoided and, furthermore, th ey can be homogeneously applied. The experimental results of a tin oxide ga s sensor show, that the sensitivity towards nitrogen oxide can be improved by external electric fields. In conclusion, suggestions are made to impleme nt this feature for innovative gas sensors with micro-hot plates. (C) 2001 Elsevier Science B.V. All rights reserved.