First-principles investigation of copper diffusion barrier performance in defective 2D layered materials
Manareldeen Ahmed1, Yan Li2, Wenchao Chen1
1College 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.
Nanotechnology
|January 5, 2022
Summary
This study reveals that molybdenum disulfide (MoS2) with sulfur vacancies offers superior copper diffusion barrier performance compared to graphene and hexagonal boron nitride (hBN). These 2D materials with defects are crucial for advanced electronics.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- 2D layered materials are crucial for advanced electronics.
- Vacancy defects in 2D materials can act as diffusion pathways for copper (Cu).
- Effective diffusion barriers are needed to prevent Cu accumulation and ensure device reliability.
Purpose of the Study:
- To investigate the diffusion barrier performance of various 2D layered materials containing pre-existing vacancy defects for copper.
- To evaluate the impact of different vacancy types and 2D structures on copper diffusion.
- To understand the relationship between defect structure and diffusion barrier properties.
Main Methods:
- First-principles density functional theory (DFT) calculations were employed.
- Climbing image-nudged elastic band (CI-NEB) method was used to calculate energy barriers.
- Analysis of charge density difference and Bader charge transfer was performed.
Main Results:
- Molybdenum disulfide with sulfur vacancies (MoS2-V2S) exhibited the highest diffusion energy barrier for copper.
- Hexagonal boron nitride with nitrogen vacancies (hBN-VN) and graphene with carbon vacancies (graphene-VC) showed lower but significant barrier performance.
- The energy barrier was found to be proportional to the diffusion path length.
- Copper diffusion modulated the electronic and magnetic properties of the 2D materials.
- Significant charge transfer was observed between copper and the barrier layers.
Conclusions:
- MoS2-V2S demonstrates excellent potential as an ultra-thin diffusion barrier for copper.
- The presence and type of vacancy defects significantly influence the diffusion barrier performance of 2D materials.
- These findings provide valuable insights for designing advanced 2D material-based diffusion barriers in microelectronics.
