Li Yue-Hui, Qi Rui-Shi, Shi Ruo-Chen, Hu Jian-Nan, Liu Zhe-Tong, Sun Yuan-Wei, Li Ming-Qiang, Li Ning, Song Can-Li, Wang Lai, Hao Zhi-Biao, Luo Yi, Xue Qi-Kun, Ma Xu-Cun, Gao Peng
International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China.
Proc Natl Acad Sci U S A. 2022 Feb 22;119(8). doi: 10.1073/pnas.2117027119.
Interface phonon modes that are generated by several atomic layers at the heterointerface play a major role in the interface thermal conductance for nanoscale high-power devices such as nitride-based high-electron-mobility transistors and light-emitting diodes. Here we measure the local phonon spectra across AlN/Si and AlN/Al interfaces using atomically resolved vibrational electron energy-loss spectroscopy in a scanning transmission electron microscope. At the AlN/Si interface, we observe various interface phonon modes, of which the extended and localized modes act as bridges to connect the bulk AlN modes and bulk Si modes and are expected to boost the phonon transport, thus substantially contributing to interface thermal conductance. In comparison, no such phonon bridge is observed at the AlN/Al interface, for which partially extended modes dominate the interface thermal conductivity. This work provides valuable insights into understanding the interfacial thermal transport in nitride semiconductors and useful guidance for thermal management via interface engineering.
由异质界面处的几个原子层产生的界面声子模式在诸如氮化物基高电子迁移率晶体管和发光二极管等纳米级高功率器件的界面热导率中起主要作用。在这里，我们使用扫描透射电子显微镜中的原子分辨振动电子能量损失光谱法测量了AlN/Si和AlN/Al界面上的局部声子光谱。在AlN/Si界面处，我们观察到各种界面声子模式，其中扩展模式和局域模式充当连接体AlN模式和体Si模式的桥梁，并有望促进声子传输，从而对界面热导率有显著贡献。相比之下，在AlN/Al界面处未观察到这种声子桥，对于该界面，部分扩展模式主导界面热导率。这项工作为理解氮化物半导体中的界面热传输提供了有价值的见解，并为通过界面工程进行热管理提供了有用的指导。
