Methodology for thermal diffusivity determination of metallic films at room temperature

An analytical model and a methodology for thermal diffusivity determination of metallic thin films at atmospheric pressure and room temperature are discussed. The analytical model is based on the one-dimensional heat conduction equation which allows us to estimate the thermal diffusivity value through the initial heating slope. To determine the thermal diffusivity value of metallic nanofilms, controlled micropulses were applied on them in order to measure changes in the electrical resistance and to estimate the corresponding changes of temperature in the transitory regime, where only the metallic film is heated. The proposed analytical model and the methodology were used to characterize Au and Al thin films thermally deposited on glass substrates. Preliminary results gave thermal diffusivity values of (40 ± 4) × 10^-6 m²/s for an Au(40 nm) film, and (25 ± 3) ±10^-6 m²/s for an Al(40 nm) film at room conditions (298 K, and atmospheric pressure).