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 maximum power generated,

${P}_{\text {max}}$

, per conduction cross-sectional area at a given temperature difference. Optimization of

${P}_{\text {max}}$

in these Si IC TEGs with respect to design and processing parameters remains an open issue. Here the dependence of

${P}_{\text {max}}$

on dopant density in Si thermopiles is examined both experimentally and by developing a simple physics-based model using empirical material parameters. Experimentally,

${P}_{\text {max}}$

improved by

$\sim 1.8\times $

with increasing dopant density from

${3} \times {10}^{{17}}$

${4} \times {10}^{{18}}$

cm ⁻³ . Modeling shows that

${P}_{\text {max}} \propto $

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

${P}_{\text {max}}$

to have a maximum at densities above 10 ¹⁹ cm ⁻³ and then decline at higher densities. Without parasitics

${Z}$

and

${P}_{\text {max}}$

would continue to increase roughly as (density) ^0.4 . The results emphasize the importance of minimizing parasitics.

Prabuddha Madusanka

Publications