Intrinsic electron mobility and lattice thermal conductivity of β-Si3N4 from first-principles

Silicon nitride based materials have emerged as the promising candidates for high-power electronics and nextgeneration gate dielectrics. Herein, the crucial characteristics of electron mobility and lattice thermal conductivity of /%-Si3N4 are investigated from first-principles. The predicted electron mobility and averaged lattice thermal conductivity is 228.4 cm2/Vs and 325.06 W/m center dot K at 300 K, which demonstrates a good agreement with literature data. The electron mobility exhibits strong temperature-dependence at a low carrier concentration where the polar-optical phonon scattering dominates. For the heavy doping case, the ionized impurity scattering becomes dominant. A well-trained momentum tensor potential (MTP) with an accuracy comparable to density functional theory shows advantages in predicting thermal transport properties over a large-scale system containing thousands of atoms. The relaxation lifetimes for heat-carrying acoustic phonons are over tens of picoseconds which can explain the high thermal conductivity of /%-Si3N4, but the nanoscale grain size crucially limits the thermal transport properties.

Automated summary

Silicon nitride based materials have been investigated for their potential applications in high-power electronics and next-generation gate dielectrics. This study focuses on the crucial characteristics of electron mobility and lattice thermal conductivity of %-Si3N4 using first-principles calculations. The predicted electron mobility and averaged lattice thermal conductivity at 300 K are 228.4 cm2/Vs and 325.06 W/m center dot K, respectively, showing good agreement with literature data. The results reveal the strong temperature dependence of electron mobility and the dominant scattering mechanisms at different carrier concentrations, as well as the limitations imposed by nanoscale grain sizes on thermal transport properties.