Thermal Disturbance of Thin Films Pair: Cross-Plane Thermal Energy Transfer

Abstract

Thermal energy transfer across a silicon–aluminum thin films pair is considered. The thin films pair is thermally disturbed from the silicon film edge by a repetitive temperature pulses while phonon transport in the film pairs is examined. The transient frequency dependent Boltzmann transport equation is solved numerically incorporating the appropriate initial and boundary conditions. Thermal boundary resistance is adopted at the thin films interface and electron–phonon coupling is introduced to account for the thermal communication of electron and lattice subsystems in the aluminum film. The influence of repetition of temperature disturbance on the phonon transport characteristics is assessed. The numerical code developed is validated through the thermal conductivity data reported in the previous study. It is found that thermal conductivity predictions agree well with the experimental data. The long pulse temperature disturbance from the silicon edge results in large phonon intensity oscillations in the silicon and the aluminum films. The ballistic phonons contribute significantly to damping of phonon intensity oscillations in the silicon film. The magnitude of temperature jump at the film edges and the films pair interface remains low for the frequency dependent solution of the Boltzmann equation.