NIRT: Phonon Transport in Nanostructures with Application to Ultrathin Silicon-on-Insulator (SOI) Transistors

Carnegie Mellon University, Pittsburgh PA

Investigators

Abstract

Proposal Number: 0103082 Principal Investigator: Mehdi Asheghi Abstract This proposal was received in response to NSE, NSF-0019. The project is focused on the study of two major nanoscale phenomena: (a) phonon transport in single crystal silicon layer of thickness in the range of 10-50 nm and (b) ballistic phonon transport near hotspots ( appr. 10 nm) in the active region of silicon-on-insulator (SOI) transistors. The experimental part of the study involves the very first measurements of thermal conductivity of nanometer size, single crystal silicon layer and ballistic phonon transport near a hotspot in a transistor. Transient and steady state heat transfer experiments on nanostructures at both room and cryogenic temperatures will be performed to reveal the fundamentals of phonon transport at nanometer scales. The theoretical effort focuses on numerical simulations of phonon Boltzmann transport equation (BTE) in the relaxation time approximation, accounting for phonon dispersion as well as frequency dependent phonon mean free paths in silicon. The analytical work will take advantage of the experimental data and numerical simulations to introduce simple, yet physically realistic, expressions for phonon transport in nanostructures, which can be used for rapid electrical/thermal simulation.