Thermal barrier effect from internal pore channels on thickened aluminum nanofilm

High thermal conductivity nanofilms play a key role in the heat dissipation of microdevices, and the preparation process greatly influences the thermal conductivity of the nanofilms. In this study, four Al nanofilms with different thicknesses were fabricated via the electron beam evaporation method, and their effective thermal conductivity (ETC) values were measured using a specially designed microsensor-based third harmonic 3ω method. Due to the internal pore channels and nanometer-level feature size, the ETC of nanofilms exhibited a downward trend when the thickness increases. Significantly, the pores produced by the preparation induce the electron-phonon nonequilibrium effect inside the film, resulting in an anomalous change of the film thermal conductivity versus the thickness.