Ahmed Manareldeen, Li Yan, Chen Wenchao, Li Er-Ping
College of Information Science and Electronics Engineering, Zhejiang University, Haining, Zhejiang Province, 314400, China, and also with Zhejiang Provincial Key Laboratory of Advanced Microelectronic Intelligent Systems and Applications, Hangzhou 310027, People's Republic of China.
Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province, College of Information Engineering, China Jiliang University, Hangzhou, Zhejiang Province, 310027, China, and also with Zhejiang Provincial Key Laboratory of Advanced Microelectronic Intelligent Systems and Applications, Hangzhou, Zhejiang Province 310027, People's Republic of China.
Nanotechnology. 2022 Jan 24;33(16). doi: 10.1088/1361-6528/ac4879.
This paper investigates the diffusion barrier performance of 2D layered materials with pre-existing vacancy defects using first-principles density functional theory. Vacancy defects in 2D materials may give rise to a large amount of Cu accumulation, and consequently, the defect becomes a diffusion path for Cu. Five 2D layered structures are investigated as diffusion barriers for Cu, i.e. graphene with C vacancy, hBN with B/N vacancy, and MoSwith Mo/2S vacancy. The calculated energy barriers using climbing image-nudged elastic band show that MoS-Vhas the highest diffusion energy barrier among other 2D layers, followed by hBN-Vand graphene. The obtained energy barrier of Cu on defected layer is found to be proportional to the length of the diffusion path. Moreover, the diffusion of Cu through vacancy defects is found to modulate the electronic structures and magnetic properties of the 2D layer. The charge density difference shows that there exists a considerable charge transfer between Cu and barrier layer as quantified by Bader charge. Given the current need for an ultra-thin diffusion barrier layer, the obtained results contribute to the field of application of 2D materials as Cu diffusion barrier in the presence of mono-vacancy defects.
本文采用第一性原理密度泛函理论研究了具有预先存在空位缺陷的二维层状材料的扩散阻挡性能。二维材料中的空位缺陷可能会导致大量铜的积累，因此，缺陷成为铜的扩散路径。研究了五种二维层状结构作为铜的扩散阻挡层，即具有C空位的石墨烯、具有B/N空位的hBN以及具有Mo/2S空位的MoS。使用爬坡图像推挤弹性带计算的能垒表明，MoS-V在其他二维层中具有最高的扩散能垒，其次是hBN-V和石墨烯。发现在缺陷层上铜的能垒与扩散路径的长度成正比。此外，发现铜通过空位缺陷的扩散会调节二维层的电子结构和磁性。电荷密度差表明，如通过巴德电荷量化的那样，铜和阻挡层之间存在相当大的电荷转移。鉴于当前对超薄扩散阻挡层的需求，所获得的结果有助于二维材料在存在单空位缺陷时作为铜扩散阻挡层的应用领域。
