Yan Shumin, Gao Ruiling, Hu Shunbo, Wang Yin
Physics Department, International Center of Quantum and Molecular Structures, Institute for the Conservation of Cultural Heritage, Materials Genome Institute, Shanghai University, 200444 Shanghai, People's Republic of China.
Key Laboratory of Silicate Cultural Relics Conservation (Shanghai University), Ministry of Education, Shanghai 200444, People's Republic of China.
J Phys Condens Matter. 2024 Oct 14;37(2). doi: 10.1088/1361-648X/ad83a2.
During the line width reduction, electron scattering caused by various defects in metal interconnects increases dramatically, which causes leakage or short circuit problems in the device, reducing device performance and reliability. Point defects are one of the important factors. Here, using density functional theory and non-equilibrium Green's function methods, we systematically study the effects of point defects on the transport properties of metals Al, Cu, Ag, Ir, Rh, and Ru, namely vacancy defects and interstitial doping of C atom. The results show that the conductivity of all systems decreases compared to perfect systems, because defects cause unnecessary electron scattering. Since the orbital hybridization of the C atom with the Al, Cu and Ag atoms is stronger than that metals Ir, Rh and Ru, the doping of C atom significantly reduces the conductivity of metals Al, Cu and Ag compared to vacancy defects. In contrast, vacancy defects have a greater impact than doping on the transport properties of metals Ir, Rh and Ru, which is mainly attributed to the larger charge transfer of the host atoms around the vacancies caused by lattice distortion. In addition, metal Rh exhibits excellent conductivity in all systems. Therefore, in order to optimize the transport properties of interconnect metals, our work points out that the doping of impurity atoms should be avoided for metals Al, Cu and Ag, while the presence of vacancy defects should be avoided for metals Ir, Rh and Ru, and Rh may be an excellent candidate material for future metal interconnects.
在金属线宽减小过程中，金属互连中各种缺陷引起的电子散射急剧增加，这会导致器件出现漏电或短路问题，从而降低器件性能和可靠性。点缺陷是重要因素之一。在此，我们使用密度泛函理论和非平衡格林函数方法，系统地研究了点缺陷对金属Al、Cu、Ag、Ir、Rh和Ru传输性质的影响，即空位缺陷和C原子的间隙掺杂。结果表明，与完美体系相比，所有体系的电导率均降低，因为缺陷会导致不必要的电子散射。由于C原子与Al、Cu和Ag原子的轨道杂化比与金属Ir、Rh和Ru的更强，与空位缺陷相比，C原子掺杂显著降低了金属Al、Cu和Ag的电导率。相比之下，空位缺陷对金属Ir、Rh和Ru传输性质的影响比掺杂更大，这主要归因于晶格畸变导致空位周围主体原子的电荷转移更大。此外，金属Rh在所有体系中都表现出优异的导电性。因此，为了优化互连金属的传输性质，我们的工作指出，对于金属Al、Cu和Ag应避免杂质原子的掺杂，而对于金属Ir、Rh和Ru应避免空位缺陷的存在，并且Rh可能是未来金属互连的一种优异候选材料。
