Design and Characterization of Micro Thermoelectric Cross-Plane Generators With Electroplated Bi₂ Te₃ , Sbₓ Tey , and Reflow Soldering

We demonstrate and discuss the fabrication of cross-plane microthermoelectric generators with electrochemically deposited thermoelectric materials. A new process based on two layers of photoresist is presented to deposit the legs on the final substrate. The n-type Bi 2 Te 3 , Cu, and p-type Sb x Te y are integrated into the generator. The deposition of antimony telluride is performed to the largest thickness reported to date. The influence of thermal annealing on the material properties is studied. A new flip-chip reflow soldering process with Bi 57 Sn 42 Ag 1 soldering paste is presented that allows for enhanced thermal coupling of the generators. The manufactured generators are electrically and thermally fully characterized. They generate up to 1.63 μW cm -2 K -2 , which corresponds to a maximum power density of 2434.4 μW cm -2 .