Micromachined radial thermoelectric modules for power generation using hot gas streams

This paper presents the design, fabrication, and characterization

of silicon-micromachined thermoelectric generator

(TEG) modules (13-mm diameter and 0.36 mm thick) for power

generation from hot gas streams. Individual TEG modules consist

of radially oriented thermoelements on a thermally insulating

annular polyimide layer spanning between inner and outer silicon

fin structures. Hot gas flows through a center orifice, establishing

a radial thermal gradient across the thermopile, thus generating

an output voltage. The concept is demonstrated using thin-film

metal thermoelements, where, for a 195 ◦C gas stream, an open-circuit

voltage of 80 mV is generated and 0.8 μW of power

(0.02 mW/cm³ power density) is delivered to a 2-kΩ resistive

load. Analytic thermal and electrical models are presented and

shown to match well the experimental thermal and electrical

measurements. This paper serves as a stepping stone toward the

development of superior-performing TEG modules using semiconductor

thermoelements.