Scattering of g-process longitudinal optical phonons at hotspots in silicon

Sinha, S. and Schelling, P. K. and Phillpot, S. R. and Goodson, K. E.. (2005) Scattering of g-process longitudinal optical phonons at hotspots in silicon. Journal of Applied Physics, 97 (2). 023702. ISSN 00218979

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Transistors with gate lengths below 100 nm generate phonon hotspots with dimensions on the order of 10 nm and peak power densities of about 50 W/μm3. This work employs molecular dynamics to investigate the impact of lattice energy density on phonon scattering at the hotspot. The hotspot studied in this work consists of longitudinal optical phonons involved in the g-type intervalley scattering of conduction electrons in silicon. A comparison of the decay modes in hotspots with high and moderate energy densities reveals that the decay mechanisms are the same but the relaxation rates differ. Scattering occurs through a three phonon process of the form LO→LA+TA, involving the zone-edge transverse acoustic modes. An increase in the energy density from a moderate value of 5 to 125 W/μm3 changes the relaxation time from 79 to 16 ps, approximately proportional to the the maximum initial amplitude of the phonons. This work improves the accuracy of the scattering rates of optical phonons and helps in advancing the electro-thermal modeling of nanotransistors.

Item Type: Article
InterNano Taxonomy: Nanomanufacturing Characterization Techniques > Thermal Analysis
Nanoscale Objects and Nanostructured Materials > Nanowires > Semiconductor nanowires
Nanoscale Objects and Nanostructured Materials > Nanodevice Structures
Collections: Nanomanufacturing Research Collection
Depositing User: Moureen Kemei
Date Deposited: 12 Mar 2010 15:36
Last Modified: 12 Mar 2010 15:36

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