A batch process micromachined thermoelectric energy harvester: fabrication and characterization

Abstract

Micromachined thermopiles are considered as a cost-effective solution for energy harvesters working at a small temperature difference and weak heat flows typical for, e.g., the human body. They can be used for powering autonomous wireless sensor nodes in a body area network. In this paper, a micromachined thermoelectric energy harvester with 6 μm high polycrystalline silicon germanium (poly-SiGe) thermocouples fabricated on a 6 inch wafer is presented. An open circuit voltage of 1.49 V and an output power of 0.4 μW can be generated with 3.5 K temperature difference in a model of a wearable micromachined energy harvester of the discussed design, which has a die size of 1.0 mm × 2.5 mm inside a watch-size generator.

Manufacturing and Characterization of a Thermoelectric Energy Harvester Using the CMOS-MEMS Technology

“…In this work, we develop a thermoelectric energy harvester using the commercial CMOS process. The fabrication energy harvester in this work is easier than that of Su et al [13], Huesgen et al [14], Yuan et al [16] and Kouma et al [17]. The output power of the energy harvester in this work exceeds that of Kao et al [18] MEMS devices made by the commercial CMOS process are called CMOS-MEMS technology [19][20][21].…”

“…Recently, many studies have employed MEMS technology to develop various energy harvesters. For instance, Su et al [13] presented a micromachined thermoelectric energy harvester with 6 µm high polycrystalline silicon germanium thermocouples. The area of the harvester was 1 mmˆ2.5 mm.…”

Simulation of maximum power in the wearable thermoelectric generator with a small thermopile

“…Nevertheless, poly-Si and poly-SiGe have been used for fabrication of micromachined thermopiles because these materials are typical for the microelectronics industry (Strasser et al 2002;Wang et al 2009;Su et al 2010;Xie et al 2010). Such thermoelectric materials cannot reach the power calculated in this paper.…”

“…Smaller and cheaper thermocouples can be produced by using MEMS or microelectronics technologies. For example, Su et al (2010) recently demonstrated a 6-lm-tall poly-SiGe thermopile. At the minimum height of 10 lm modeled in this Section, an aspect ratio of 1.4 allows the output voltage of 0.5 V. This corresponds to the lateral dimension of the leg of 7.3 lm that is quite relaxed for modern microelectronics processes.…”

Current Developments of Energy Scavenging, Converting and Storing in WSNs

“…proposed a micromachined thermoelectric energy harvester with 6 µm high polycrystalline silicon germanium (poly-SiGe) thermocouples fabricated on a 6 inch wafer [31].…”