A Porous Silicon Humidity Sensor

Humidity sensors have wide industrial applications in areas such as automobile industry, food processing and evaluation of plastic encapsulations in IC packaging. In this paper we report on the use of porous silicon as a material for humidity sensing. The structure used to detect humidity changes is essentially a parallel plate capacitor, with porous silicon acting as the dielectric. This paper presents results on the characterisation of the material for different formation conditions. Initial experiments have shown high sensitivity to humidity changes, under certain conditions a 900% change in capacitance was recorded for a relative humidity change of 64% at room temperature.