Nanoporous thin films have received attention in the microelectronics field for their application as next-generation low-k inner-layer dielectric (ILD) materials due dielectric constants approaching 1.4. In addition, emerging applications as thermal insulation for microsystems aim to exploit the materials’ unique thermal properties in sensor and component products. However, its thermal properties can vary greatly depending on fabrication processes and material morphology. In addition, a variety of transport phenomena are present and delineation among them is difficult. In this work, we examine heat transport in aerogel, one of the most common embodiments of nanoporous materials, to identify the main modes of energy transport. We employ a modified diffusion-limited cluster aggregation (DLCA) technique to simulate aerogel’s highly porous, amorphous solid structure. Network models then simulate heat transport through the structure to extract effective thermal conductivity. The models are verified by comparing calculated bulk data to published aerogel literature. Preliminary models yield thermal conductivity on the order of 0.010 W/m*K, which is consistent with published data for aerogel films. These values vary inversely with porosity of the aerogel following an inverse power law often used to fit aerogel experimental data. This methodology is most useful for examining the sensitivity of thermal conductivity to salient structural features such as porosity, pore size distribution, solid thermal properties, average branch width, and sub-continuum phenomena. The results of this study can be used as a predictive tool in optimizing aerogel fabrication process to yield morphologies that best-suit the requirements of the application.
- Heat Transfer Division and Electronic and Photonic Packaging Division
Thermal Transport Network Model for High-Porosity Materials: Application to Nanoporous Aerogels
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Smith, BR, Beutler, PD, & Amon, CH. "Thermal Transport Network Model for High-Porosity Materials: Application to Nanoporous Aerogels." Proceedings of the ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. Heat Transfer: Volume 4. San Francisco, California, USA. July 17–22, 2005. pp. 955-961. ASME. https://doi.org/10.1115/HT2005-72662
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