Post-CMOS FinFET Integration of Bismuth Telluride and Antimony Telluride Thin-Film-Based Thermoelectric Devices on SoI Substrate

This letter reports, for the first time, heterogeneous integration of bismuth telluride (Bi₂Te₃) and antimony telluride (Sb₂Te₃) thin-film-based thermoelectric (TE) devices on a CMOS substrate. The TE films are deposited on a silicon-on-insulator substrate with FinFETs (3-D multiple gate field effect transistors) via a characterized TE-film coevaporation and shadow-mask patterning process using predeposition surface treatment methods for reduced TE-metal contact resistance. As a demonstration vehicle, a 2 × 2 mm²-sized integrated planar thermoelectric generator (TEG) is shown to harvest 0.7 μW from 21-K temperature gradient. Transistor performance showed no significant change upon post-CMOS TEG integration, indicating, for the first time, the CMOS compatibility of the Bi₂Te₃ and Sb₂Te₃ thin films, which could be leveraged for realization of high-performance integrated micro-TE harvesters and coolers.