Power-Compensated Single-Crystal Silicon Thermopiles for Differential Scanning Calorimetry (DSC)

We demonstrate power-compensated MEMS thermopiles for chip-based differential scanning calorimetry (DSC). Different from the conventional DSC apparatus (using a pair of crucibles and macroscopic thermocouples) that suffers from low responsivity (~1-10 mV/W) and slow heating rates (~1-5°C/s), our MEMS differential thermopiles, integrated with 54 pairs of P-type/N-type single-crystal silicon thermocouples, offer outstanding power responsivity (~100V/W) and intrinsic heating rate of >10
⁵
°C/s. The temperature responsivity (28mV/°C) is also ~7 times higher than the commercialized devices (~4mV/°C). We then demonstrate rapid DSC measurement on indium melting. Proportional-integral-derivative (PID) control circuitry and algorithm are implemented for programmed heating rates up to 100°C/s. Simultaneously, another PID control scheme is employed for power compensation. We measure the latent heat of fusion for indium to be ~27.5J/g at 2 and 10°C/s, which agrees with the nominal value (28.53 J/g). Our MEMS thermopiles hold promise for quantitative analysis of endothermic /exothermic processes in various fields.