Analysis and simulation of forcing the limits of thermal sensing for microbolometers in CMOS-MEMS technology

Abstract

Room-temperature highly sensitive microbolometers are becoming very attractive in infrared (IR) sensing with the increase in demand for the internet of things (IOT), night vision, and medical imaging. Different techniques, such as building extremely small-scale devices (nanotubes, etc.) or using 2D materials, showed promising results in terms of high sensitivity with the cost of challenges in fabrication and low-noise readout circuit. Here, we propose a new and simple technique on the application of joule heating on a clamped-clamped beam without adding any complexity. It provides much better uniformity in temperature distribution in comparison to conventional joule heating, and this results in higher thermal stresses on fixed ends. This consequently brings around 60.5x improvement in the overall temperature sensitivity according to both theory and COMSOL (multiphysics solver). The sensitivity increased with the increase in the stiffness constant, and it was calculated as 134 N/m for a device with a 60.5x improvement. A considerable amount of decrease in the operation temperature (36x below 383 K and 47x below 428 K) was achieved via a new technique. That's why the proposed solution can be used either to build highly reliable long-term devices or to increase the thermal sensitivity.