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

Abstract

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.