Complete analytical modeling and analysis of micromachined thermoelectric uncooled IR sensors

This paper deals with a complete analytical modeling and analysis of thermoelectric uncooled infrared sensors compatible with CMOS technology. The operating principle involves a localized thermal assessment resulting from IR radiation absorption, a micromachined membrane on which PolySi/Al thermojunctions have been deposited causing an internal self-generated electromotive force. The model put forward is based on dividing the sensor into three zones, each one being the subject of a thorough thermal study (conduction, convection and radiation thermal effect). Through the analytical thermal gradient analysis developed in each zone of the structure (absorber, part of thermoelectric transducer layer placed under the absorber, thermoelectric transducer) we are able to predict the sensitivity, detectivity and the noise equivalent power to the sensor. Thus, such a kind of analytical approach is worth of interest to optimize thermopile sensor design parameters.