Closed-Loop System Dual-Membrane for Mitigating Outgassing Induced Pressure Change in Infrared Sensors

This study presents a novel closed-loop micro-electromechanical system infrared sensor that features dual-membranes, mitigating drift caused by the outgassing induced pressure change from the sensor hermetic package. Outgassing has an impact on the sensor thermal resistance. The closed-loop system controls the feedback heaters on the membrane directly to measure incident radiation, effectively eliminating the influence of thermal resistance on sensor performance. A comprehensive theoretical analysis and system-level modeling were performed. The sensor, along with the readout ASIC, was successfully fabricated on a single die. Experiments demonstrate that the closed-loop system reduces the effects of pressure change due to outgassing and input radiation on sensitivity by 24 times and 8 times, respectively. This method cancels sensor drift without increasing fabrication complexity, addressing a significant limitation of conventional infrared sensors and facilitating cost-effective packaging.