A split-flux model for phonon transport near hotspots
A split-flux model for phonon transport near hotspots
复制标题
热点附近声子输运的分流模型
DOI：
10.1115/imece2004-61949
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
K. Goodson
中科院分区：
文献类型：
--
作者：
S. Sinha;E. Pop;K. Goodson
半导体器件中峰值电场附近强烈的电子-声子散射导致纳米级声子热点，其功率密度约为1 W/μm3。为了研究热点对声子输运的影响，我们在弛豫时间近似下求解了声子玻尔兹曼输运方程，得到了声子模之间偏离平衡的情况。偏离函数分为两个贡献：一个来自远平衡发射声子，另一个来自近平衡热声子。该模型的预测进行了比较与现有的数据在硅中的弹道声子输运。计算的瞬态和稳态的声子占据数的设备的几何形状的纵向光学声子的电场上的顺序为1 MV/m的优势。由于这些模式的低群速度，在热点处存在能量停滞，这导致对于90 nm体硅器件约13%的过度温升。在器件切换期间，当占空比为30%时，在100 ps的周期内，发射的声子有足够的时间完全弛豫。
Intense electron-phonon scattering near the peak electric field in a semiconductor device results in nanometer-scale phonon hotspots with power densities on the order of 1 W/μm3 . To study the impact of the hotspot on phonon transport, we solve the phonon Boltzmann transport equation under the relaxation time approximation to yield the departure from equilibrium amongst phonon modes. The departure function is split into two contributions: one arising from the far-from-equilibrium emitted phonons and the other from the near-equilibrium thermal phonons. The model predictions are compared with existing data on ballistic phonon transport in silicon. Computations of transient and steady state phonon occupation numbers for a device geometry show the predominance of longitudinal optical phonons for electric fields on the order of 1 MV/m. Due to the low group velocity of these modes, there is an energy stagnation at the hotspot which results in an excess temperature rise of about 13% for a 90 nm bulk silicon device. During device switching, emitted phonons have sufficient time to relax completely when the duty cycle is 30% on a period of 100 ps.Copyright © 2004 by ASME