This paper presents the fabrication and characterization of energy harvesting thermoelectric micro generators using the commercial complementary metal oxide semiconductor (CMOS) process. The micro generator consists of 33 thermocouples in series. Thermocouple materials are p-type and n-type polysilicon since they have a large Seebeck coefficient difference. The output power of the micro generator depends on the temperature difference in the hot and cold parts of the thermocouples. In order to increase this temperature difference, the hot part of the thermocouples is suspended to reduce heat-sinking. The micro generator needs a post-CMOS process to release the suspended structures of hot part, which the post-process includes an anisotropic dry etching to etch the sacrificial oxide layer and an isotropic dry etching to remove the silicon substrate. Experiments show that the output power of the micro generator is 9.4 mW at a temperature difference of 15 K.
References
[1]
Gardner, J.W.; Varadan, V.K.; Awadelkarim, O.O. Microsensors MEMS and Smart Devices; John Wiley & Sons Ltd.: Chichester, UK, 2001.
[2]
Glatz, W.; Schwyter, E.; Durrer, L.; Hierold, C. Bi2Te3-based flexible micro thermoelectric generator with optimized design. J. Microelectromech. Syst. 2009, 18, 763–772.
[3]
Lee, C.; Xie, J. Design and optimization of wafer bonding packaged microelectromechanical systems thermoelectric power generators with heat dissipation path. J. Vacuum Sci. Technol. B 2009, 27, 1267–1271.
[4]
Huesgen, T.; Woias, P.; Kockmann, N. Design and fabrication of MEMS thermoelectric generators with high temperature efficiency. Sens. Actuators A 2008, 145, 423–429.
[5]
Wang, Z.Y.; van Andel, Y.; Jambunathan, M.; Leonov, V.; Elfrink, R.; Vullers, R.J.M. Characterization of a bulk-micromachined membraneless in-plane thermopile. J. Electron. Mater. 2011, 40, 499–503.
[6]
Su, J.; Leonov, V.; Goedbloed, M.; van Andel, Y.; de Nooijer, M.C.; Elfrink, R.; Wang, Z.; Vullers, R.J.M. A batch process micromachined thermoelectric energy harvester: fabrication and characterization. J. Micromech. Microeng. 2010, 20, doi:10.1088/0960-1317/20/10/104005.
[7]
Nishibori, M.; Shin, W.; Tajima, K.; Houlet, L.F.; Izu, N.; Matsubara, I.; Murayama, N. Catalyst combustors with B-Doped SiGe/Au thermopile for micro-power-generation. Jpn. J. Appl. Phys. 2006, 45, L1130–L1132.
[8]
Strasser, M.; Aigner, R.; Lauterbach, C.; Sturm, T.F.; Franosch, M.; Wachutka, G. Micromachined CMOS thermoelectric generators as on-chip power supply. Sens. Actuators A 2004, 114, 362–370.
[9]
Baltes, H.; Brand, O. CMOS-based microsensors and packaging. Sens. Actuators A 2001, 92, 1–9.
[10]
Dai, C.L.; Hsu, H.M.; Tsai, M.C.; Hsieh, M.M.; Chang, M.W. Modeling and fabrication of a microelectromechanical microwave switch. Microelectr. J. 2007, 38, 519–424.
[11]
Kao, P.H.; Dai, C.L.; Hsu, C.C.; Lee, C.Y. Fabrication and characterization of a tunable in-plane resonator with low driving voltage. Sensors 2009, 9, 2062–2075.
[12]
Dai, C.L.; Lu, P.W.; Wu, C.C.; Chang, C. Fabrication of wireless micro pressure sensor using the CMOS process. Sensors 2009, 9, 8748–8760.
[13]
Liu, M.C.; Dai, C.L.; Chan, C.H.; Wu, C.C. Manufacture of a polyaniline nanofiber ammonia sensor integrated with a readout circuit using the CMOS-MEMS technique. Sensors 2009, 9, 869–880.
[14]
Yang, M.Z.; Dai, C.L.; Wu, C.C. A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip. Sensors 2011, 11, 11112–11121.
[15]
Sato, N.; Kuwabara, K.; Ono, K.; Sakata, T.; Morimura, H.; Terada, J.; Kudou, K.; Kamei, T.; Yano, M.; Machida, K.; Ishii, H. Monolithic integration fabrication process of thermoelectric and vibrational devices for microelectromechanical system power generator. Jpn. J. Appl. Phys. 2007, 46, 6062–6067.
[16]
Kao, P.H.; Shin, P.J.; Dai, C.L.; Liu, M.C. Fabrication and characterization of CMOS-MEMS thermoelectric micro generators. Sensors 2010, 10, 1315–1325.
