MAGNESIUM ALUMINUM SPINEL THIN-FILM AS A HUMIDITY SENSOR

This paper discusses the use of Mg-Al spinel as a sensitive material suitable for application in humidity sensors. Mg-Al spinel thin films were deposited on a Si/SiO2 substrate by the radiofrequency technique, using a target of sintered MgAl2O4 powder. SEM and XPS measurements were performed in order to investigate their microstructure and surface composition. Electrical measurements were carried out in a suitable test chamber, where temperature and humidity were controlled. The electrical behaviour of our samples in the relative humidity range from 2% up to 98% was explored. Significant changes in resistance and good reversibility obtained without the need for heat cleaning are the most interesting results.