Inherent area selective deposition of silicon dioxide in multilayer 3D SiOx–SiNx stacks

• Published in: Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vacuum, surfaces, and films, 2024-09, Vol.42 (5)
• Main Authors: Sondhi, Kartik, Ross, Stephen, Nag, Joyeeta, Guo, X. C., Zhao, Dexin, Rajashekhar, Adarsh, Kanakamedala, Senaka
• Format: Article
• Language: English
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/6.0003790

Device scaling for future semiconductor technologies is driving the adoption of innovative methods for miniaturizing semiconductor chips. One promising approach that has garnered significant interest for sub-10 nm device scaling is area selective deposition (ASD). In this study, we demonstrate the feasibility of ASD of silicon dioxide (SiO2) on –OH terminated surfaces (silicon oxide: SiOx) but not on –NH terminated surfaces (silicon nitride: SiNx) for 2D blanket, 2D patterned, and 3D stacks using a novel precursor: Orthrus. To achieve this, we optimized the SiOx and SiNx layers to enhance the –OH and –NH surface bonds, respectively. Using x-ray photo spectroscopy analysis, we showed that SiO2 selectively deposits on SiOx without any nucleation delay compared to SiNx. We have demonstrated the inherent selective deposition of approximately ∼4 nm on 2D patterned structures and ∼3.7 nm on 3D stacks by fine-tuning the atomic layer deposition process. This selective thickness is >250% compared to a previously shown selective SiO2 deposition process in the literature. Finally, we also showed that the step coverage of selective SiO2 growth in 3D stacks is ∼1. This study highlights the potential pathway for performing ASD of commonly used SiO2 in 3D high-aspect-ratio stacks.