Li Qinshu, Liu Fang, Hu Song, Song Houfu, Yang Susu, Jiang Hailing, Wang Tao, Koh Yee Kan, Zhao Changying, Kang Feiyu, Wu Junqiao, Gu Xiaokun, Sun Bo, Wang Xinqiang
Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen, 518055, China.
State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China.
Nat Commun. 2022 Aug 20;13(1):4901. doi: 10.1038/s41467-022-32600-w.
Understanding thermal transport across metal/semiconductor interfaces is crucial for the heat dissipation of electronics. The dominant heat carriers in non-metals, phonons, are thought to transport elastically across most interfaces, except for a few extreme cases where the two materials that formed the interface are highly dissimilar with a large difference in Debye temperature. In this work, we show that even for two materials with similar Debye temperatures (Al/Si, Al/GaN), a substantial portion of phonons will transport inelastically across their interfaces at high temperatures, significantly enhancing interface thermal conductance. Moreover, we find that interface sharpness strongly affects phonon transport process. For atomically sharp interfaces, phonons are allowed to transport inelastically and interface thermal conductance linearly increases at high temperatures. With a diffuse interface, inelastic phonon transport diminishes. Our results provide new insights on phonon transport across interfaces and open up opportunities for engineering interface thermal conductance specifically for materials of relevance to microelectronics.
了解金属/半导体界面间的热传输对于电子产品的散热至关重要。在非金属中，主要的热载体——声子，被认为在大多数界面上进行弹性传输，但也有少数极端情况除外，即形成界面的两种材料差异极大，德拜温度相差悬殊。在这项工作中，我们表明，即使对于德拜温度相似的两种材料（铝/硅、铝/氮化镓），在高温下，相当一部分声子也会非弹性地穿过它们的界面，从而显著提高界面热导率。此外，我们发现界面锐度强烈影响声子传输过程。对于原子级锐化的界面，声子能够进行非弹性传输，并且在高温下界面热导率呈线性增加。而对于具有扩散界面的情况，非弹性声子传输则会减少。我们的研究结果为声子跨界面传输提供了新的见解，并为专门针对微电子相关材料设计界面热导率开辟了机会。
