金膜非平衡传热过程中电子-界面热输运研究

Study on electron-interface thermal transport in non-equilibrium heat transfer of gold nanofilms

中文关键词: 时域热反射  金纳米薄膜  电子-声子耦合  超快激光  电子-界面热输运

英文关键词: time domain thermoreflectance  gold nanofilms  electron-phonon coupling  ultrafast laser  electron-interface scattering

中文摘要:

      随着半导体与微电子技术的高速发展,高频器件内金属薄膜与电介质间的电子-界面热输运成为重要的研究课题。本文基于双温度模型讨论了金膜非平衡传热过程中可能存在的四种边界条件。结合时域热反射法测量了不同厚度的金膜,其中,79 nm金膜在电子-声子耦合过程中,受到金/基底界面的影响较小,可以忽略,获得了与理论预测结果一致的电子-声子耦合因子；对于较薄的50 nm金膜,边界上的电子-声子散射对超快非平衡传热过程的贡献不可忽略,因此测量得到的电子-声子耦合因子低于79 nm 金膜的值。该研究揭示了界面载流子散射可以对不同厚度和基底条件下的金属薄膜内超快非平衡热输运过程的贡献规律,为深入研究微纳电子器件的微观热输运问题提供了重要的实验支撑。

英文摘要:

      With the rapid development of semiconductor and microelectronics technology, electron-interface thermal transport between metal thin films and dielectrics in high-frequency devices has become an important research subject. In this work, gold films of different thicknesses were measured by time-domain thermoreflectance method. And based on the two temperature model, the non-equilibrium heat transfer in these gold films were discussed with four kinds of different boundary conditions. Among them, the influence from gold/substrate interface on the electron-phonon coupling process for the 79 nm gold film is relatively low , so that can be ignored, which is consistent with the theoretical predictions. However, the contribution of electron-phonon boundary scattering to the ultrafast non-equilibrium heat transfer process in a thinner gold film of 50 nm thickness is much stronger and cannot be neglected. As a result, the measured electron-phonon coupling factor is lower than that of 79 nm sample. This study has revealed how much the interfacial carrier scattering will contribute to ultrafast nonequilibrium heat transport process in metal nano-films with different thicknesses and substrates, and provides in-depth experimental analysis of the heat transport in micro-nano electronic devices.