Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Nitride Interfacial Defect Layers

International Journal of Physics | Vol. 11, No. 7, July 2020 | pp. 49–56

DOI: 10.46882/2020/IJP/000123

Research Article

Title: Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Nitride Interfacial Defect Layers

Names of Authors: M. G. Richter¹, S. P. Nair²

Authors’ Affiliations:
¹ Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
² Department of Physics, University of Kerala, Trivandrum, India

Abstract: Minimizing thermal transport across semiconductor boundary layers is crucial for designing high-efficiency solid-state thermoelectric cooling devices and optimizing microelectronic heat sinks. This paper uses molecular dynamics simulations to quantify thermal dispersion metrics and track phonon wavepacket scattering at defective silicon-nitride (Si-Si3N4) interfaces. We constructed atomistic models using the optimized Tersoff potential, incorporating varying concentrations of interfacial point defects and atomic roughness steps. Longitudinal and transverse acoustic phonon wavepackets were generated with narrow frequency spreads centered between 2.0 THz and 8.0 THz. The computational data demonstrate that high-frequency acoustic phonons (f greater than 5.0 THz) undergo strong diffuse scattering at the rough interface, dropping the transmission coefficient from 0.85 down to 0.22. This diffuse scattering is driven by localized strain fields and localized interface vibrational modes. The overall interfacial thermal conductance was calculated to decrease by 48.0% when the interfacial roughness parameter scaled from 0.1 nm to 0.6 nm at 300.0 K. These molecular dynamics calculations clarify the atomic-scale mechanisms restricting heat carrier propagation, helping engineers design targeted thermal barriers for nanoscale electronics.

Keywords: Thermal dispersion; phonon wavepacket; molecular dynamics; interface roughness; thermoelectric cooling; nitride interfaces

Manuscript Timeline: Received: March 11, 2020; Revised: May 19, 2020; Accepted: June 11, 2020; Published: July 09, 2020

Citation: Richter, M. G., & Nair, S. P. (2020). Thermal Dispersion Metrics and Phonon Wavepacket Scattering at Silicon-Nitride Interfacial Defect Layers. International Journal of Physics, 11(7), 49–56.

Subscribe to read the full article: https://internationalscholarsjournals.org/subscribe-to-read