Molecular Dynamics of Atomic Layer Deposition: Sticking Coefficient Investigation

TJ Kunene and LK Tartibu and S Karimzadeh and PO Oviroh and K Ukoba and TC Jen, APPLIED SCIENCES-BASEL, 12, 2188 (2022).

DOI: 10.3390/app12042188

This study focused on the atomic scale growth dynamics of amorphous Al2O3 films microscale structural relaxation. Classical Molecular Dynamics (MD) can not entirely model the challenging ALD dynamics due to the large timescales. The all-atom approach has rules based on deposition actions modelled MD relaxations that form as input to attain a single ALD cycle. MD relaxations are used to create a realistic equilibrium surface. This approach is fitting to this study as the investigation of the sticking coefficient is only at the first monolayer that includes the layering of a hydroxyl surface of alumina. The study provides insight between atomic-level numerical information and experimental measurements of the sticking coefficient related to the atomic layer deposition. The MD modeling was for the deposition of Al2O3, using trimethylaluminum (TMA) and water as precursors. The film thickness of 1.7 angstrom yields an initial sticking coefficient of TMA to be 4.257 x 10(-3) determined from the slope of the leading front of the thickness profile at a substrate temperature of 573 K. This work adds to the knowledge of the kinetic nature of ALD at the atomic level. It provides quantitative information on the sticking coefficient during ALD.

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