Comparative Modeling of Four-Ended, Modified Four-Ended, and Double-Ended Beam MEMS Thermopile Sensor Structures for Functional Area Optimization

Research on infrared thermopiles has seen substantial advancements in fabrication techniques and material synthesis in order to maximize the thermoelectric performance of the sensors. In the field of microelectromechanical systems (MEMS) where space optimization is key to effective miniaturization, determining the optimal layout for thermopile elements within specific area constraints is of high importance. This study presents a comparative modeling of three beam-type thermopile structures to maximize the output voltage for a given functional area. Four-ended beam (FEB), modified FEB, and double-ended beam (DEB) thermopile structures and the subsequent variations in their component dimensions were modeled analytically and through finite element simulation to determine the optimal variation for each structure. DEB was the standout structure with an optimal configuration possessing an absorber size of $2.304 \times 10^{5} \mu m^{2}$ and displaying an output voltage of $6.158~{mV}$, responsivity of $295.537 \mathrm{~V}/\mathrm{W}$, detectivity of $1.321 \times 10^{8} {~cm} * {~Hz}^{1 / 2} * {~W}^{-1}$, and a time constant of $61.58{~ms}$ from an input power of $80 {~W}/{m}^{2}$. The optimal configurations of the FEB and modified FEB achieved output voltages of $3.783~{mV}$ and $3.679~{mV}$, respectively.