MEMS/ECD Method for Making Bi₂₋ₓSbₓTe₃ Thermoelectric Devices

A method of fabricating Bi2–xSbxTe3-based thermoelectric microdevices involves a combination of (1) techniques used previously in the fabrication of integrated circuits and of microelectromechanical systems (MEMS) and (2) a relatively inexpensive MEMS-oriented electrochemical- deposition (ECD) technique. The devices and the method of fabrication at an earlier stage of development were reported in “Sub milli meter-Sized Bi2–xSbxTe3 Thermoelectric Devices” (NPO-20472), NASA Tech Briefs, Vol. 24, No. 5 (May 2000), page 44. To recapitulate: A device of this type generally contains multiple pairs of n- and p-type Bi2–xSbxTe3 legs connected in series electrically and in parallel thermally. The Bi2–xSbxTe3 legs have typical dimensions of the order of tens of microns. Metal contact pads and other non-thermoelectric parts of the devices are fabricated by conventional integrated-circuit and MEMS fabrication techniques. The Bi2–xSbxTe3 thermoelectric legs are formed by electrodeposition, through holes in photoresist masks, onto the contact pads.