Performance analysis of thermoelectric energy generator with stacked polysilicon germanium thermocouples

It has been shown that the performance of a thermoelectric energy generator (TEG) is dependent upon both the number of thermocouples connected in electrical series and the Seebeck coefficients of the thermocouple materials. This work proposes a TEG with stacked polysilicon germanium (poly-SiGe) thermocouples for higher thermoelectric conversion efficiency. Different from the co-planar thermocouple design where the P- and Nthermolegs on the same plane, the stacked thermocouple design is by having the P-thermoleg on top of the Nthermoleg to reduce the thermocouple footprint and increase area density, hence improving harvesting capability. A thermal model is developed to simulate that a TEG with one stacked thermocouple at 64 x 2 & mu;m can achieve 0.131 & mu;W/cm2K2 power factor and 37.01 V/cm2K voltage factor. The voltage factor is about 2times of the TEG with co-planar thermocouples. This improvement is the solution to low output voltage that has been plaguing TEG development. Simulation has also shown that a TEG with two or three stacked thermocouples on the same footprint can further increase the voltage factor to 52.57 or 64.51 V/cm2K, respectively