INTEGRATED SEMICONDUCTOR GAS SENSORS EVALUATION WITH AN AUTOMATIC TEST SYSTEM

Systematic gas sensitivity and dynamic characteristics of SnO2 gas sensors are reported. A complete automatic test system controlled with a micromputer has been developed and used for experimental procedures. The installation allows the monitoring of a large range of different vapours, and six different gases independently or simultaneously. The humidity can be varied from 0% to 95% inside the small volume test chamber, where the temperature as well as moisture are continuously measured. Dynamic behaviour, such as gas response and recovery time, has been investigated. The low thermal inertia of the integrated gas sensors enables dynamic measurements and observations of relaxation phenomena to be made. An integrated heater serves to control precisely the temperature of the sensors. Thus, activation energies in different atmospheres can be estimated. The aim of these measurements is to obtain information on the conductance mechanisms in sputtered tin oxide thin films. © 1990.