A humidity sensor of a new type

Abstract The recently most talked about and used humidity sensors are capacitive sensors with a thin polymer film as the sensitive layer. Despite the many advantages, these sensors have shown some reliability problems caused by special effects of the polymer (e.g. swelling) and the direct moisturising action on the electrical transducing elements. To overcome these disadvantages we have developed a new type of humidity sensor, a piezoresistive transducer, fabricated with integrated circuit technology. In this paper we describe the sensor design, methods of analytical simulation of the sensor behaviour and measured characteristics of fabricated sensors. The tested elements showed a fast transient response to humidity and a very good reproducibility.