Research on Thermal Field Coupling Simulation of Silicon-based Micro-hotplate CO Sensor

In response to the increasing incidents of carbon monoxide (CO) poisoning, this study proposes a design method for a comprehensive CO sensor based on a silicon micro hotplate. Finite element software is used for thermal field coupling simulation to establish a thermal field based on the electro-thermal coupling model. The study investigates the influence of the supporting membrane type, supporting membrane thickness, and operating temperature on the thermal interference between sensor units. The research results indicate that using a composite structure as the supporting layer effectively reduces overall stress magnitude, decreases deformations generated by the micro hotplate, and improves the stability of the structure. In this study, through the optimization of the supporting layer material, it is found that setting the thickness of SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> to 0.5 um and Si <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> to 1 um yields appropriate results. Additionally, regarding the width of the cantilever beam, it is found that a width of 151 um is suitable. Based on the simulation results of the micro hotplate CO gas sensor, a sensor array with multiple temperature zones is designed to achieve the detection of different gases at different temperatures by gas-sensitive materials. The simulation results show that under a 5V applied voltage, the micro hotplate can be divided into three regions: high-temperature, medium-temperature, and low-temperature, with a temperature difference of 100° C between adjacent regions. These research findings are of significant guidance for the design optimization of micro hotplates.