High-Performance Silicon Nanowire Array Electronic Thermometer Fabricated Using CMOS-MEMS Techniques

This work proposes a high-performance silicon nanowire (SiNW) array thermometer for real-time detection of human body temperature. We have achieved highly controllable, low-cost, and scalable fabrication of the SiNW thermometers by using CMOS-compatible microfabrication. The surface morphology and resistance of SiNWs are unstable due to their high surface reactivity. Here, we developed a fully encapsulated structure that employs silicon nitride and silicon oxide films to tightly enclose the SiNW; this strategy significantly improves the long-term stability of the thermometer. Moreover, the encapsulated structure brings better mechanical reliability to protect the SiNWs from breakage, thereby significantly enhancing the yield of the thermometer. Multiple SiNWs simultaneously detect temperature, enabling the thermometer to achieve a signal intensity of 0.179 μA, a signal-to-noise ratio of 36 dB, and a power consumption of 3.71 μW. These characteristics reduce the complexity and cost of the backend signal processing circuit, and we developed a high-performance SiNW array body temperature detection system based on the low-cost STM32 microcontroller, achieving the detection of human body temperature with an accuracy of ±0.1 °C. The SiNW-based thermometer is compact, highly stable, cost-effective, and energy-efficient, demonstrating significant potential for integration into wearable devices for real-time body temperature monitoring.