Molecular dynamics simulation on longitudinal optical phonon mode decay and heat transport in a silicon nano-structure covered with oxide films

Tomofumi Zushi, Yoshinari Kamakura, Kenji Taniguchi, Iwao Ohdomari, Takanobu Watanabe

    Research output: Contribution to journalArticle

    6 Citations (Scopus)

    Abstract

    A series of molecular dynamics (MD) simulations have been conducted to investigate the heat transport in terms of the phonon dynamics in nanoscale silicon (Si). This work is motivated by a concern over the stagnation of heat at the drain region of nanoscopic transistors, owing to this, a large amount of optical phonons with a low group velocity are emitted from hot electrons, which are ballistically transferred through channel region. The point of this work is the explicit inclusion of the SiO2 film in the MD simulation of the Si lattice. The calculation results show that longitudinal optical (LO) phonons decay faster as Si lattice thickness decreases and turn into acoustic phonons. In contrast, thermal diffusion rate decreases with Si lattice thickness. Both the decay rate of LO phonons and thermal diffusion rate are not governed by oxide thickness. These results imply that the phonon scattering at the SiO 2/Si interface is enhanced by thinning the Si layer. In nanoscopic devices, a thin Si layer is effective in diminishing the optical phonons with a low group velocity, but it hinders the subsequent heat transport.

    Original languageEnglish
    Article number010102
    JournalJapanese Journal of Applied Physics
    Volume50
    Issue number1
    DOIs
    Publication statusPublished - 2011 Jan

    Fingerprint

    Oxide films
    oxide films
    Molecular dynamics
    Phonons
    molecular dynamics
    heat
    Silicon
    phonons
    Computer simulation
    silicon
    decay
    simulation
    Thermal diffusion
    thermal diffusion
    group velocity
    low speed
    Phonon scattering
    Hot electrons
    Hot Temperature
    hot electrons

    ASJC Scopus subject areas

    • Engineering(all)
    • Physics and Astronomy(all)

    Cite this

    Molecular dynamics simulation on longitudinal optical phonon mode decay and heat transport in a silicon nano-structure covered with oxide films. / Zushi, Tomofumi; Kamakura, Yoshinari; Taniguchi, Kenji; Ohdomari, Iwao; Watanabe, Takanobu.

    In: Japanese Journal of Applied Physics, Vol. 50, No. 1, 010102, 01.2011.

    Research output: Contribution to journalArticle

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    AU - Ohdomari, Iwao

    AU - Watanabe, Takanobu

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