Gradient area-selective deposition for seamless gap-filling in 3D nanostructures through surface chemical reactivity control

Integrating bottom-up and top-down fabrication techniques can overcome limits in nanofabrication. Here authors demonstrate an approach for area selective deposition using Ti as an inhibitor in the atomic layer deposition process to achieve controlled growth of seamless TiO2 layers on 3D structures. The integration of bottom-up fabrication techniques and top-down methods can overcome current limits in nanofabrication. For such integration, we propose a gradient area-selective deposition using atomic layer deposition to overcome the inherent limitation of 3D nanofabrication and demonstrate the applicability of the proposed method toward large-scale production of materials. Cp(CH3)(5)Ti(OMe)(3) is used as a molecular surface inhibitor to prevent the growth of TiO2 film in the next atomic layer deposition process. Cp(CH3)(5)Ti(OMe)(3) adsorption was controlled gradually in a 3D nanoscale hole to achieve gradient TiO2 growth. This resulted in the formation of perfectly seamless TiO2 films with a high-aspect-ratio hole structure. The experimental results were consistent with theoretical calculations based on density functional theory, Monte Carlo simulation, and the Johnson-Mehl-Avrami-Kolmogorov model. Since the gradient area-selective deposition TiO2 film formation is based on the fundamentals of molecular chemical and physical behaviours, this approach can be applied to other material systems in atomic layer deposition.