Peng Wei-Tsu, Chen Fu-Ren, Lu Ming-Chang
Department of Mechanical Engineering, National Yang Ming Chiao Tung University, Hsinchu, 300, Taiwan.
Department of Mechanical Engineering, National Taiwan University, Taipei, 106, Taiwan.
Phys Chem Chem Phys. 2021 Sep 22;23(36):20359-20364. doi: 10.1039/d1cp02774c.
Copper nano-interconnects are ubiquitous in semiconductor devices. The electrical and thermal properties of copper nanowires (CuNWs) profoundly affect the performance of electronics. In contrast to the intensively studied electrical properties of CuNWs, the thermal conductivities of CuNWs have seldom been examined. In this study, the electrical resistivity and thermal conductivity of single CuNWs were investigated. The Bloch-Grüneisen formula was introduced to determine the mechanisms responsible for the obtained electrical resistivity of the CuNWs. High residual resistivity was found, which indicated strong structural scattering on the electron transport resulting from defect scattering and boundary scatterings at the copper-copper oxide interface and grain boundaries. The mean structural scattering distance was employed to appreciate the degree of structural scattering in the CuNWs. The residual resistivity and electron-phonon coupling parameter were found to increase with the degree of structural scattering. Moreover, the unified thermal resistivity was introduced to illustrate the mechanisms responsible for the CuNWs' thermal conductivities. Similarly, large values of residual unified thermal resistivity and electron-phonon-induced unified thermal resistivity were found. The obtained unified thermal resistivities of the CuNWs could also be qualitatively explained by the degree of structural scattering in the CuNWs. The results suggested that structural scattering was predominant in the electrical current transport and heat transfer in the nanowires. This study revealed the mechanisms of electrical resistivity and thermal conductivity of CuNWs, and the insights could assist in improving the design of semiconductor architectures.
铜纳米互连在半导体器件中无处不在。铜纳米线（CuNWs）的电学和热学性质深刻影响着电子器件的性能。与对CuNWs电学性质的深入研究相比，其热导率很少被研究。在本研究中，对单根CuNWs的电阻率和热导率进行了研究。引入布洛赫 - 格律恩森公式来确定导致所测得的CuNWs电阻率的机制。发现了高残余电阻率，这表明在铜 - 氧化铜界面和晶界处的缺陷散射和边界散射导致电子输运存在强烈的结构散射。采用平均结构散射距离来评估CuNWs中的结构散射程度。发现残余电阻率和电子 - 声子耦合参数随结构散射程度的增加而增加。此外，引入统一热阻率来说明导致CuNWs热导率的机制。同样，发现了较大的残余统一热阻率和电子 - 声子诱导的统一热阻率。所测得的CuNWs的统一热阻率也可以通过CuNWs中的结构散射程度进行定性解释。结果表明，结构散射在纳米线中的电流传输和热传递中占主导地位。本研究揭示了CuNWs的电阻率和热导率机制，这些见解有助于改进半导体架构的设计。
