As atomic layer deposition (ALD) emerges as a method to fabricate architectures with atomic precision, emphasis is placed on understanding surface reactions and nucleation mechanisms. ALD of titanium dioxide with TiCl4and water has been used to investigate deposition processes in general, but the effect of surface termination on the initial TiO2nucleation lacks needed mechanistic insights. This work examines the adsorption of TiCl4on Cl−, H−, and HO− terminated Si(100) and Si(111) surfaces to elucidate the general role of different surface structures and defect types in manipulating surface reactivity of growth and non‐growth substrates. The surface sites and their role in the initial stages of deposition are examined by X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Density functional theory (DFT) computations of the local functionalized silicon surfaces suggest oxygen‐containing defects are primary drivers of selectivity loss on these surfaces.
Area‐selective deposition (ASD) is a forefront nanopatterning technique gaining substantial attention in the semiconductor industry. While current research primarily addresses single‐material ASD, exploring multi‐material ASD is essential for mitigating complexity in advanced nanopatterning. This study describes molybdenum hexafluoride (MoF6)‐mediated fluorination/passivation of the hydroxylated SiO2(SiO2‒OH) at 250 °C as a new method to pacify nucleation during subsequent ZnO and TiO2atomic layer deposition (ALD). In contrast, Al2O3ALD is not passivated on the fluorinated SiO2(SiO2‒F). The study further shows that Mo ALD using MoF6and silane (1 wt% SiH4in Ar) selectively proceeds on hydrogen‐terminated Si (Si‒H), whereas SiO2‒OH becomes fluorine‐passivated without observable Mo deposition. This enables subsequent ZnO and TiO2ASD on Mo versus SiO2‒F, as confirmed by X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM). Proposed growth and inhibition mechanisms highlight the importance of the metal oxide precursor in achieving selectivity. Taken together, self‐aligned Mo/ZnO and Mo/TiO2nanoribbons are demonstrated on coplanar nanoscale Si‒H/SiO2‒OH patterns by sequentially integrating two individual ASD processes: 1) Mo ASD on Si‒H versus SiO2‒OH; and 2) ZnO or TiO2ASD on Mo versus SiO2‒F. This work highlights the potential for this approach in new ASD systems.
more » « less- PAR ID:
- 10502434
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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