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

Nguyen, Chi Thang; Cho, Eun-Hyoung; Gu, Bonwook; Lee, Sunghee; Kim, Hae-Sung; Park, Jeongwoo; Yu, Neung-Kyung; Shin, Sangwoo et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

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(CH<sub>3</sub>)<sub>5</sub>Ti(OMe)<sub>3</sub> is used as a molecular surface inhibitor to prevent the growth of TiO<sub>2</sub> film in the next atomic layer deposition process. Cp(CH<sub>3</sub>)<sub>5</sub>Ti(OMe)<sub>3</sub> adsorption was controlled gradually in a 3D nanoscale hole to achieve gradient TiO<sub>2</sub> growth. This resulted in the formation of perfectly seamless TiO<sub>2</sub> 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 TiO<sub>2</sub> 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.