Thermoelectric Infrared Sensors with High Responsivity for Automotive Applications

This paper presents the structure and fabrication process of a thermoelectric infrared sensor that provides high responsivity and a low cost potential. The processes for obtaining a precisely patterned Au-black infrared absorbing layer and reducing the internal stress of the Si3N4 layer deposited by LP-CVD achieve both high responsivity and an excellent time constant. A prototype sensor, having external dimensions of 160μm×160μm and six pairs of thermopiles, achieved responsivity of 2100V/W and a time constant of 25msec at a pressure of 7.33Pa. This Performance is suitable for automotive applications.