Miniaturized thermoelectric generators based on poly-Si and poly-SiGe surface micromachining

We report on miniaturized thermoelectric generators (TEGs) which are being developed to convert waste heat into a few microwatts of electrical power, sufficient to supply microelectronic circuitry. A BiCMOS realization using standard materials is favored to make these generators amenable to low cost applications. In order to optimize our device, the design and the material properties have been studied. The use of micromachining techniques allowed us to improve the thermal efficiency of the generator significantly. Low thermal conductivity of the thermoelectric materials proved to be the most important factor to increase the output power. The materials we have investigated are poly-Si and poly-SiGe. Experimental results obtained from fabricated devices show good agreement with the predictions of thermal simulations. (C) 2002 Elsevier Science B.V. All rights reserved.