This paper presents a high-performance micro-electromechanical systems (MEMS) thermopile infrared detector. It consists of a double-end beam and a dual-layer thermocouple structure, which improves the responsivity of the detector. The etch-stop structure is integrated into the detector to prevent isotropic etching-caused damage on the device. The responsivity of the detector achieved 1151.14 V/W, and the measured response time was 14.46 ms. The detector had the potential to work as a high-precision temperature sensor and as a vacuum sensor.

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·Hz1/2/W, and a response time of 26.9 ms. The design optimization of this detector provides a reference for further development of IR detectors.

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The micro-electromechanical system (MEMS) infrared thermopile is the core working device of modern information detection systems such as spectrometers, gas sensors, and remote temperature sensors. We presented two different structures of MEMS infrared thermopiles based on suspended film structures. They both deposited silicon nitride over the entire surface as a passivated absorber layer in place of a separate absorber zone, and the thermocouple strip was oriented in the same direction as the temperature gradient. The same MEMS preparation process was used and finally two different structures of the thermopile were characterized separately for testing to verify the impact of our design on the detector. The test results show that the circular and double-ended symmetrical thermopile detectors have responsivities of 27.932 V/W and 23.205 V/W, specific detectivities of 12.1×107 cm·Hz1/2·W−1 and 10.1×107 cm·Hz1/2·W−1, and response time of 26.2 ms and 27.06 ms, respectively. In addition, rectangular double-ended symmetric thermopile has a larger field of view than a circular thermopile detector, but is not as mechanically stable as a circular thermopile.