Design and Fabrication of a Low-Cost Thermopile Infrared Detector

In this paper, we design and optimize a low-cost, closed-film structure of a microelectromechanical systems (MEMS) thermopile infrared detector. By optimizing the circular arrangement of thermocouple strips and the thermal isolation design of the cold end to pursue a higher temperature difference, in addition to eliminating the absorption region, silicon nitride is deposited on the whole device surface as a passivated absorption layer. This reduces the cost while maintaining the voltage response and is suitable for mass production. The optimized detector had a 22.6% improvement in the response rate to 34.2 V/W, a detection rate of 1.02 × 10⁸ cm·Hz^1/2/W, and a response time of 26.9 ms. The design optimization of this detector provides a reference for further development of IR detectors.