Enhanced thermoelectric performance in a CMOS-MEMS microgenerator using suspended p/n-polysilicon thermocouples

Abstract This study presents a complementary metal oxide semiconductor (CMOS)-compatible thermoelectric microgenerator ( μ TEG) that introduces a dual-path thermal engineering strategy to enlarge the on-chip temperature gradient. The design combines (i) oxide-capped hot anchors with intrinsically low thermal conductivity to suppress upward heat leakage and (ii) a stacked-metal cold junction suspended above a reactive in etching (RIE)-defined silicon cavity that acts as an integrated heat spreader. A sequential post-CMOS release—RIE of oxide followed by RIE of silicon—forms long air gaps and a deep under-cavity, confining heat transport to the p/n-polysilicon thermocouple legs while remaining fully design-rule compliant and fabrication-robust. Experiments show that the measured output voltage of the μ TEG reaches 16.1 mV at a temperature difference of 8 K. The corresponding voltage factor and power factor of the μ TEG are 1.25 mV mm −2 K −1 and 0.49 nW mm −2 K −2 , respectively.