High heat flux sensitivity of large-scale integrated silicon CMOS micro thermoelectric devices

Accurate and sensitive heat flux sensing is essential for next-generation thermal management and adaptive control systems, particularly for waste heat below 200 °C, a range still lacking effective utilization technologies despite major advances in high-temperature heat recovery. Conventional heat flux sensors often face difficulty with achieving optimal detection sensitivity while minimizing interference with the measurement target. In response, we propose novel cavity-free thermoelectric (TE) devices, realized through standard silicon CMOS technology, wherein strategic miniaturization and large-scale integration synergistically reduce thermal resistance and substantially elevate heat flux sensitivity. By incorporating 70668 units of silicon nanowire (Si-NW) thermoelements, our device achieves a remarkable heat flux sensitivity (HFS) of 12.14 μV/(W/m 2 ), with a corresponding normalized sensitivity per unit area of 590 mV/W, enabling detection of heat flow with minimal temperature changes. The work represents a significant step forward in realizing compact, highly sensitive, and CMOS-compatible heat flux sensors, with wide-ranging applications in thermal-aware engineering systems , ambient temperature environments and dynamic thermal management technologies . • Cavity-free CMOS-compatible TE devices demonstrate high heat flux sensitivity. • Integrated up to 70668 silicon nanowire thermoelectric units in a 5 mm × 5 mm chip. • Achieved record-high heat flux sensitivity of 590 mV/W with excellent linearity. • Short Si-NWs and low doping enhance sensitivity and output. • Architecture ensures low thermal resistance and robust vertical heat flow conduction.