Design and Optimization of a Novel Multiheater Microhotplate With Thermal Crosstalk

As demand grows for high-sensitivity and high-selectivity gas sensors in the Internet of Things (IoT) and environmental monitoring fields, metal oxide semiconductor (MOX) gas sensors based on microhotplates have attracted significant research interest due to their low-power consumption and high integration. While array designs can address the issue of low sensor selectivity, integrating multiple sensor elements may result in increased power consumption. To overcome this limitation, this article proposes a novel multiheater integrated microhotplate design based on thermal crosstalk, integrating multiple heaters on a single microhotplate to generate encodable multiple temperature areas. Through COMSOL finite element simulation, the effects of heater sizes, geometry, and thickness on the performance of the microhotplate were systematically studied. The results indicate that with a heater radius of $100~\mu $ m, the microhotplate exhibits excellent temperature uniformity at a working temperature of $300~^{\circ }$ C, with more than 70% of the heating area having a temperature gradient of less than $10~^{\circ }$ C. Additionally, the optimized heater geometry significantly reduces the mechanical deformation of the microhotplate, ensuring structural stability. Most notably, the thermal crosstalk effect effectively reduces the power consumption of the microhotplate. At a working temperature of $300~^{\circ }$ C, the dual-heater design consumes approximately 4.68 mW less power than the single-heater configuration. By introducing an etched window design, the thermal efficiency of the microhotplate is further enhanced, with a peak temperature increase of approximately $40~^{\circ }$ C. The innovative multiheater microhotplate design based on thermal crosstalk achieves low-power temperature control across all heaters, laying a solid foundation for the development and widespread adoption of high-performance portable gas sensors.