MEMS Based High Sensitivity Calorimetry

The fundamental study of phase transformations continues to be a key for successful implementation of metals and alloys in micro- and nano-scale structures in integrated circuitry and magnetic recording devices and systems. The thermodynamic and thermokinetic properties of extremely thin layers can be altered due to the relative effect of boundaries and interfaces on the volume of the material. Calorimetry at the nano-scale requires measurement sensitivity on the order of 1 nJ or better, which requires improved thermal design, development of thermal modeling, and development of experimental measurement techniques. In this report, the specific heat of 144 nm thick CoFe layer is measured, using frequency-domain Joule heating and thermometry (3ω-technique), on Cu/SiO₂ and Cu/SiO₂/CoFe suspended bridges. Analyses of the heat transfer in suspended structures are performed to establish guidelines for design and fabrication of small-scale differential scanning calorimeters.