Progress Towards a Micromachined Thermoelectric Generator using PbTe and PbSnSeTe Thin Films
FLORIDA UNIV GAINESVILLE DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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This paper presents etching techniques and metal contact resistance studies for vapor-deposited PbTe and PbSnSeTe films to enable micromachining of thermoelectric TE generators within integrated MEMS devices e.g. micro heat engines, microcombustors. Films of up to 10 micrometers were achieved using 100 silicon substrates. Single-crystal films were achieved using CdTe or ZnTe buffer layers, while polycrystalline films were formed on thermally-oxidized silicon. Processes using a bromine-based wet etch and methane-based ICP plasma etch yielded etch rates of 3 micrometermin and 0.65 micrometersmin, respectively, with high selectivities 101 to photoresist, silicon and SiO2. Electrical resistivity van der Pauw and metal contact resistance transfer length method test structures were used to characterize patterned PbTe and PbSnSeTe films and the contact resistance with a variety of metals AuCr, Au, Pt, Ni, Cu, Pt. Film resistivities of 5-300 momega-cm and ohmic contacts with specific contact resistivities of 0.4-40 momega-sq cm were achieved.
- Electrical and Electronic Equipment
- Fabrication Metallurgy