La0.7Sr0.3MnO3 suspended microbridges for uncooled bolometers made using reactive ion etching of the silicon substrates

Suspended La0.7Sr0.3MnO3 (LSMO) microbridges were fabricated using standard silicon micromachining techniques. First epitaxial LSMO thin films were deposited on SrTiO3 (STO) buffered Si (0 0 1) substrates by molecular-beam epitaxy. A simple two photolithography step process using the reactive ion etching of the silicon substrate to release the suspended microbridges was developed. The electrical resistivity as a function of temperature of 4 μm wide 50–200 μm long and 75 nm thick LSMO/STO fully processed suspended microbridges was very close to the characteristics of the initial LSMO thin films, demonstrating that the fabrication process did not degrade the quality of the LSMO. The thermal conductance of the processed bolometers was very low (of the order of 10−7 W K−1) at 300 K. These structures are promising for uncooled bolometer applications and other micro-electromechanical systems based on LSMO or other epitaxial functional oxides.

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► Suspended LSMO bridges were successfully fabricated on silicon substrates.
► The fabrication process did not degrade the electrical properties of the LSMO film.
► Thermal conductances in the order of 10−7 W K−1 were measured.