The modified electron-phonon interaction model is proposed, and the relative contributions of phonons and electrons to the thermal conduction in doped silicon films are investigated quantitatively. The carrier contributions in sub-micro scale heat conduction are validated by an order of magnitude analysis and comparison with previous data. The simulation results show that the electron contribution in Si-layer is not negligible when the doping concentration is higher than $10^{19}cm^{-3}$, which can be classified as semimetal or metal by the value of its electrical resistivity at 300 K. The electron thermal conductivity increases with increasing doping density, and its fraction is about 57.2% of the total thermal conductivity when the doping concentration is $5.0{ imes}10^{20}cm^{-3}$ and silicon film thickness 100 nm.