Scaling of Power Generation With Dopant Density in Integrated Circuit Silicon Thermoelectric Generators

摘要

Integrated circuit (IC) thermoelectric generators (TEGs) fabricated by standard "65 nm" Si processing have been shown to be potentially competitive with (Bi, Sb)(2)Te-3 TEGs in terms of maximumpower generated, P-max, per conduction cross-sectional area at a given temperature difference. Optimization of Pmax in these Si IC TEGs with respect to design and processing parameters remains an open issue. Here the dependence of P-max on dopant density in Si thermopiles is examined both experimentally and by developing a simple physics-based model using empirical material parameters. Experimentally, P-max improved by similar to 1.8 x with increasing dopant density from 3 x 10(17) to 4 x 10(18) cm(-3). Modeling shows that P-max proportional to thermopile figure-of-merit ZT, which scales with dopant density approximately as (density)(0.24) from 10(17) to 10(19) cm(-3). A model extrapolation to 10(20) cm(-3) predicts that parasitic resistance and thermal conductance will cause Z and P-max to have a maximum at densities above 10(19) cm(-3) and then decline at higher densities. Without parasitics Z and P-max would continue to increase roughly as (density)(0.4). The results emphasize the importance of minimizing parasitics.