Phonon radiative transport in silicon–aluminum thin films: Frequency dependent case

Non-equilibrium heating across silicon and aluminum films is considered and frequency dependent phonon radiative transport in the silicon film is incorporated while modified two-equation model is used in the aluminum film to account for the energy transport. Thermal boundary resistance is introduced across the silicon and aluminum films and electron–phonon resistance is incorporated at the interface of the aluminum film. It is found that frequency dependent solution of phonon radiative transfer equation resulted in sharper decay of equivalent equilibrium temperature than that corresponding to frequency independent solution in the silicon film.

► Temperature difference between electron and lattice sub-systems occurs at aluminum interface.
► Phonon temperature at aluminum film back becomes less than electron temperature.
► Equivalent equilibrium temperature obtained from frequency dependent solution decays sharp.
►  The effect of ballistic phonons on equivalent equilibrium temperature is more pronounced in early heating periods.