Bridging Finite Element and Molecular Dynamics for Non-Fourier Thermal Transport Near Nanoscale Hot Spot
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arXiv
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| Format: | Preprint |
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2025
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| author | Abedien, Tanvirul Feng, Tianli |
| author_facet | Abedien, Tanvirul Feng, Tianli |
| contents | Nanoscale hot spots forming tens of nanometers beneath the gate in advanced FinFET and HEMT devices drive heat transport into a non-Fourier regime, challenging conventional (Fourier-based) finite-element (FEM) analyses and complicating future thermal-aware chip design. Molecular dynamics (MD) naturally captures ballistic transport and phonon nonequilibrium, but has not been applied to hot-spot problems due to computational cost. Here, we perform the first MD simulations of hot-spot heat transfer across ballistic-diffusive regimes and benchmark them against FEM. We find that FEM using bulk thermal conductivity $κ_0$ significantly underestimates hot-spot temperature, even when the channel thickness is ~10 times the phonon mean free path, indicating persistent non-Fourier effects. We introduce a size-dependent "best" conductivity, $κ_{\mathrm{best}}$, using which FEM can reproduce MD hot-spot temperatures with high fidelity. We further decompose the MD-extracted thermal resistance into: (i) diffusive spreading, (ii) cross-plane ballistic, (iii) heat-carrier selective heating, and (iv) residual 3D ballistic-spreading resistances, and quantify each contribution. The resulting framework offers a practical route to embed non-Fourier physics into FEM for hot-spot prediction, reliability assessment, and thermally aware design of next-generation transistors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_24500 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Bridging Finite Element and Molecular Dynamics for Non-Fourier Thermal Transport Near Nanoscale Hot Spot Abedien, Tanvirul Feng, Tianli Mesoscale and Nanoscale Physics Nanoscale hot spots forming tens of nanometers beneath the gate in advanced FinFET and HEMT devices drive heat transport into a non-Fourier regime, challenging conventional (Fourier-based) finite-element (FEM) analyses and complicating future thermal-aware chip design. Molecular dynamics (MD) naturally captures ballistic transport and phonon nonequilibrium, but has not been applied to hot-spot problems due to computational cost. Here, we perform the first MD simulations of hot-spot heat transfer across ballistic-diffusive regimes and benchmark them against FEM. We find that FEM using bulk thermal conductivity $κ_0$ significantly underestimates hot-spot temperature, even when the channel thickness is ~10 times the phonon mean free path, indicating persistent non-Fourier effects. We introduce a size-dependent "best" conductivity, $κ_{\mathrm{best}}$, using which FEM can reproduce MD hot-spot temperatures with high fidelity. We further decompose the MD-extracted thermal resistance into: (i) diffusive spreading, (ii) cross-plane ballistic, (iii) heat-carrier selective heating, and (iv) residual 3D ballistic-spreading resistances, and quantify each contribution. The resulting framework offers a practical route to embed non-Fourier physics into FEM for hot-spot prediction, reliability assessment, and thermally aware design of next-generation transistors. |
| title | Bridging Finite Element and Molecular Dynamics for Non-Fourier Thermal Transport Near Nanoscale Hot Spot |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2512.24500 |