Compact Micro Thermal Sensor Based on Silicon Thermocouple Junction and Suspended Fluidic Channel

This research proposed a micro biochemical thermal sensor with compact integration capability by combining a novel single thermocouple junction and suspended microfluidic channel. While the thermal sensor was fabricated through standard MEMS processes on the silicon-on-insulator (SOI) wafer, a heavily-doped silicon of high Seebeck coefficient was employed as the highly sensitive material for thermocouple junction. To enable a high sensitivity and fast response detection, a unique structure of air-suspended bridge and a built-on SU-8 polymer microfluidic channel was fabricated to reduce heat loss and sample loading dose for trace amount of heat detection. As high as a sensitivity of 0.27 V/W and rapid thermal response less than 200 ms are achieved in this thermal sensor, which allows for the enzymatic bio-reaction heat detection and laid great potential for portable healthcare applications.