First-Principles computation-driven mechanism study of tungsten growth on alumina surfaces with TiN nano-islands

• Published in: Applied surface science 2024-11, Vol.674, p.160938, Article 160938
• Main Authors: Choi, Woojin, Lee, Sungwoo, Han, Dong-Hoon, Taek Lim, Hong, Park, Hwanyeol, Lee, Gun-Do
• Format: Article
• Language: English
• Subjects: Aluminum Oxide (Al2O3); Amorphous; Crystalline; First-principles density functional theory (DFT) calculations; Titanium Nitride (TiN); Tungsten (W)
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.160938

[Display omitted] •Our study aims to provide first-principles insights into the uniform deposition of tungsten films on amorphous/α-Al2O3 as well as the Al2O3/TiN interface.•Tungsten atom tends to be adsorbed more strongly on the Al2O3/TiN interface than it is on the bare Al2O3 and TiN surface.•Amorphous Al2O3 exhibits a stronger adsorption energy and diffusion barrier for tungsten atoms than those of α-Al2O3.•Amorphous Al2O3, which hinders tungsten migration, would be beneficial for enhancing step coverage, which is advantageous for achieving uniform thin film deposition. Strong comprehension of the tungsten film deposition process on Al2O3 substrate with TiN adhesion layer is essential to achieve high quality metal gate, but the fundamental mechanism of this process is yet to be fully understood. This study employs first-principles density functional theory (DFT) calculations to explore the mechanisms of tungsten film growth on alumina surfaces while focusing on amorphous/α-Al2O3 and interfaces with TiN nano-islands. Tungsten atoms are strongly bonded on the Al2O3/TiN interface compared to their bonding on the Al2O3 or TiN surface, regardless of the crystallinity of Al2O3. Moreover, amorphous Al2O3 surfaces exhibit stronger adsorption energies and present higher diffusion barriers for tungsten atoms compared to their crystalline counterparts, α-Al2O3, and TiN surfaces, which were also confirmed by electronic structure analysis. This enhanced adhesion on amorphous substrates suggests a potential pathway through which improve the step coverage and uniformity of tungsten thin films while addressing common issues such as void formation and non-uniform layering in high-aspect-ratio structures. Post-deposition annealing can help create crystalline tungsten films with superior conductivity. The insights gained from this work offer a computational perspective on the atomic-level interactions governing tungsten deposition, and they are expected to help producing high-quality thin films in semiconductor technologies.