The development of the micro-generator on the substrate based thin film

We fabricated bismuth-telluride based thin films and their in-plane thermoelectric micro-generators (4mmx4mm) on a glass substrate by using the flash evaporation method through shadow masks. We prepared fine powders of Bi2.0Te2.7Se0.3 (n-type) and Bi0.4Te3.0Sb1.6 (p-type). The shadow masks are fabricated by standard micro-fabrication processes such as nitridation of silicon, dry etching and wet etching. The output voltages of micro-generators are lower than that of a thermoelectric generator based on bulk materials. The main reason is because the temperature difference between cool and hot junctions of the micro-generator is small compared to a thermoelectric generator based on bulk materials. In this study, the micro-generators were fabricated on a silicon nitride substrate based thin film. By fabricating the micro-generator on the thin film substrate, a large temperature difference between cool and hot junctions is obtained due to the thin film effect and the heat radiation to air of the thin film substrate. At the silicon nitride substrate based thin films, the thermal conductivity is significantly reduced by 1.2 W/ (m K). The thin film substrate is prepared by applying the fabrication processes used for shadow masks. The silicon nitride substrate based thin film is fabricated by nitridation of silicon and then back etching the silicon wafer. The fabricated substrate thickness is 2.5 mu m and 4.5 mu m (4 mm x 4 mm). The temperature between cool and hot junctions is measured by using the noncontact thermometer which senses the far-infrared radiation. The output voltage of