arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2102.07683cond-mat.mtrl-scicond-mat.mes-hall
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6 H- SiC的准弹道热传导

Quasi-Ballistic Thermal Conduction in 6H-SiC

Zhe Cheng, Weifang Lu, Jingjing Shi, Daiki Tanaka, Nakib H. Protik, Shangkun Wang, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama, Isamu Akasaki, Hiroshi Amano, Samuel Graham

摘要:

电子器件的最小化使得相关设备的散热成为越来越大的挑战。当材料的尺寸小于声子平均自由程时,声子在没有内部散射的情况下传输,扩散热传导定律失效,导致有效热导率显著降低。本文首次报道了掺杂外延6 H-SiC和单晶多孔6 H-SiC在室温以下的热导率随温度的变化。在这些样品中观察到强烈的准弹道热传输,特别是在低温下。掺杂和结构边界被施加到调谐准弹道热输运,因为掺杂剂选择性地散射高频声子,而边界散射声子与长的平均自由程。观察到异常强的声子散射硼掺杂剂相比,氮掺杂剂。此外,在测量的热导率的数量级减少,观察到在低温下的多孔6 H-SiC相比,外延6 H-SiC。最后,第一性原理计算和一个简单的卡拉威模型建立理解测得的热导率。我们的工作揭示了对技术重要的宽带隙半导体(如6 H-SiC)中热传导的基本理解,并将影响6 H-SiC相关电子和设备的热管理等应用。

英文摘要:

The minimization of electronics makes heat dissipation of related devices an increasing challenge. When the size of materials is smaller than the phonon mean free paths, phonons transport without internal scatterings and laws of diffusive thermal conduction fail, resulting in significant reduction in the effective thermal conductivity. This work reports, for the first time, the temperature dependent thermal conductivity of doped epitaxial 6H-SiC and monocrystalline porous 6H-SiC below room temperature probed by time-domain thermoreflectance. Strong quasi-ballistic thermal transport was observed in these samples, especially at low temperatures. Doping and structural boundaries were applied to tune the quasi-ballistic thermal transport since dopants selectively scatter high-frequency phonons while boundaries scatter phonons with long mean free paths. Exceptionally strong phonon scattering by boron dopants are observed, compared to nitrogen dopants. Furthermore, orders of magnitude reduction in the measured thermal conductivity was observed at low temperatures for the porous 6H-SiC compared to the epitaxial 6H-SiC. Finally, first principles calculations and a simple Callaway model are built to understand the measured thermal conductivities. Our work sheds light on the fundamental understanding of thermal conduction in technologically-important wide bandgap semiconductors such as 6H-SiC and will impact applications such as thermal management of 6H-SiC-related electronics and devices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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