Material optimization of phosphorus-doped polycrystalline silicon germanium for miniaturized thermoelectric generator

This paper reports the results of the material optimization of phosphorus-doped polycrystalline silicon germanium (poly-SiGe) for use in thermoelectric energy harvesting. The problem of high specific contact resistance is tackled by optimizing the microfabrication process and choosing a new metal stack for interconnect. Other material properties relevant to the thermoelectric energy harvesting have also been characterized and reported. Calculations show that once the optimized process flow is adopted, the output power of a micromachined high-topography thermopile can be improved by a factor of at least 6.