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Title: Nanoscale hotspots due to nonequilibrium thermal transport.

Abstract

Recent experimental and modeling efforts have been directed towards the issue of temperature localization and hotspot formation in the vicinity of nanoscale heat generating devices. The nonequilibrium transport conditions which develop around these nanoscale devices results in elevated temperatures near the heat source which can not be predicted by continuum diffusion theory. Efforts to determine the severity of this temperature localization phenomena in silicon devices near and above room temperature are of technological importance to the development of microelectronics and other nanotechnologies. In this work, we have developed a new modeling tool in order to explore the magnitude of the additional thermal resistance which forms around nanoscale hotspots from temperatures of 100-1000K. The models are based on a two fluid approximation in which thermal energy is transferred between ''stationary'' optical phonons and fast propagating acoustic phonon modes. The results of the model have shown excellent agreement with experimental results of localized hotspots in silicon at lower temperatures. The model predicts that the effect of added thermal resistance due to the nonequilibrium phonon distribution is greatest at lower temperatures, but is maintained out to temperatures of 1000K. The resistance predicted by the numerical code can be easily integrated with continuum modelsmore » in order to predict the temperature distribution around nanoscale heat sources with improved accuracy. Additional research efforts also focused on the measurements of the thermal resistance of silicon thin films at higher temperatures, with a focus on polycrystalline silicon. This work was intended to provide much needed experimental data on the thermal transport properties for micro and nanoscale devices built with this material. Initial experiments have shown that the exposure of polycrystalline silicon to high temperatures may induce recrystallization and radically increase the thermal transport properties at room temperature. In addition, the defect density was observed to play a major role in the rate of change in thermal resistivity as a function of temperature.« less

Authors:
 [1];  [1]
  1. Stanford University, Menlo Park, CA
Publication Date:
Research Org.:
Sandia National Laboratories
Sponsoring Org.:
USDOE
OSTI Identifier:
921139
Report Number(s):
SAND2004-8037
TRN: US0800969
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ACCURACY; ACOUSTICS; APPROXIMATIONS; DEFECTS; DIFFUSION; DISTRIBUTION; HEAT SOURCES; MICROELECTRONICS; PHONONS; RECRYSTALLIZATION; SILICON; SIMULATION; TEMPERATURE DISTRIBUTION; THIN FILMS; TRANSPORT; Microelectronics-Materials-Thermal properties.; Temperature control.; Nanostructure.; Diffusion-Mathematical models.

Citation Formats

Sinha, Sanjiv, and Goodson, Kenneth E. Nanoscale hotspots due to nonequilibrium thermal transport.. United States: N. p., 2004. Web. doi:10.2172/921139.
Sinha, Sanjiv, & Goodson, Kenneth E. Nanoscale hotspots due to nonequilibrium thermal transport.. United States. doi:10.2172/921139.
Sinha, Sanjiv, and Goodson, Kenneth E. Thu . "Nanoscale hotspots due to nonequilibrium thermal transport.". United States. doi:10.2172/921139. https://www.osti.gov/servlets/purl/921139.
@article{osti_921139,
title = {Nanoscale hotspots due to nonequilibrium thermal transport.},
author = {Sinha, Sanjiv and Goodson, Kenneth E},
abstractNote = {Recent experimental and modeling efforts have been directed towards the issue of temperature localization and hotspot formation in the vicinity of nanoscale heat generating devices. The nonequilibrium transport conditions which develop around these nanoscale devices results in elevated temperatures near the heat source which can not be predicted by continuum diffusion theory. Efforts to determine the severity of this temperature localization phenomena in silicon devices near and above room temperature are of technological importance to the development of microelectronics and other nanotechnologies. In this work, we have developed a new modeling tool in order to explore the magnitude of the additional thermal resistance which forms around nanoscale hotspots from temperatures of 100-1000K. The models are based on a two fluid approximation in which thermal energy is transferred between ''stationary'' optical phonons and fast propagating acoustic phonon modes. The results of the model have shown excellent agreement with experimental results of localized hotspots in silicon at lower temperatures. The model predicts that the effect of added thermal resistance due to the nonequilibrium phonon distribution is greatest at lower temperatures, but is maintained out to temperatures of 1000K. The resistance predicted by the numerical code can be easily integrated with continuum models in order to predict the temperature distribution around nanoscale heat sources with improved accuracy. Additional research efforts also focused on the measurements of the thermal resistance of silicon thin films at higher temperatures, with a focus on polycrystalline silicon. This work was intended to provide much needed experimental data on the thermal transport properties for micro and nanoscale devices built with this material. Initial experiments have shown that the exposure of polycrystalline silicon to high temperatures may induce recrystallization and radically increase the thermal transport properties at room temperature. In addition, the defect density was observed to play a major role in the rate of change in thermal resistivity as a function of temperature.},
doi = {10.2172/921139},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2004},
month = {Thu Jan 01 00:00:00 EST 2004}
}

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