Fabrication and measured performance of a first-generation microthermoelectric cooler

• Published in: Journal of microelectromechanical systems Vol. 14; no. 5; pp. 1110 - 1117
• Main Authors: da Silva, L.W., Kaviany, M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Antimony telluride; Bismuth; bismuth telluride; Chromium; Connectors; Coolers; Cooling; Devices; Exact sciences and technology; Fabrication; Gold; Hot junctions; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Lithography; Mechanical instruments, equipment and techniques; Micromechanical devices and systems; microthermoelectric cooler; Physics; Power factor; Reactive power; Tellurium; Temperature; thermoelectric films; Thermoelectricity; Photofabrication; Patterning; Cooling; Convection; Optimization; Thermoelectric properties; Antimony telluride; microthermoelectric cooler; Thermoelectric effect; Bismuth tellurides; thermoelectric films; p type semiconductor; bismuth telluride; Photolithography; Microelectromechanical device
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2005.851846

The measured performance of a column-type microthermoelectric cooler, fabricated using vapor-deposited thermoelectric films and patterned using photolithography processes, is reported. The columns, made of p-type Sb/sub 2/Te/sub 3/ and n-type Bi/sub 2/Te/sub 3/ with an average thickness of 4.5 /spl mu/m, are connected using Cr/Au/Ti/Pt layers at the hot junctions, and Cr/Au layers at the cold junctions. The measured Seebeck coefficient and electrical resistivity of the thermoelectric films, which were deposited with a substrate temperature of 130/spl deg/C, are -74 /spl mu/V/K and 3.6/spl times/10/sup -5/ /spl Omega/-m (n-type, power factor of 0.15 mW/K/sup 2/-m), and 97 /spl mu/V/K and 3.1/spl times/10/sup -5/ /spl Omega/-m (p-type, power factor of 0.30 mW/K/sup 2/-m). The cooling performance of devices with 60 thermoelectric pairs and a column width of 40 /spl mu/m is evaluated under a minimal cooling load (thermobuoyant surface convection and surface radiation). The average cooling achieved is about 1 K. Fabrication challenges include the reduction of the column width, implementation of higher substrate temperatures for optimum thermoelectric properties, and improvements of the top connector patterning and deposition.