## 4 Conclusions  
The key strength of this study was its focus on the atomic scale growth dynamics of amorphous Al\({}_{2}\)O\({}_{3}\) films by inspecting microscale (MD) structural relaxation. The current findings add to a growing body of literature on applying the all-atom approach. There are rules based on the deposition actions to model MD relaxations of a single ALD cycle. The study supplemented the MD relaxations to create a realistic equilibrium surface by including the layering of hydroxyls on alumina. It was from a relaxed surface that an examination of the initial sticking coefficient of TMA was conducted. The study has gone some way towards enhancing understanding of the initial sticking coefficient between atomic-level numerical information and its experimental measurements related to the atomic layer deposition. Therefore, the initial sticking coefficient was determined to be 4.257 \(\times\) 10\({}^{-3}\), including error estimates from the MD model that would need improved interatomic potentials by using density functional theory (DFT) to account for the ligand exchanges in the presence of a hydroxylated surface. Notwithstanding these limitations, the study suggests that the initial sticking coefficient is an essential parameter for predicting the conformality of ALD growth. The ALD growth is calculated from the slope of the saturation profile. The saturation profile of ALD Al\({}_{2}\)O\({}_{3}\) has a near-ideal form, namely, a constant thickness of 1.7 A. This thickness develops from the first cycle, as expected for an ALD process. The process is based on repeated self-terminating and the gas-solid interactions as the surface coverage increases. Therefore, significantly beyond 50% coverage, the overall sticking coefficient decreases. This is because of the site-blocking hindering diffusion. The consequence of unavoidable -OH groups that will always be present on the surface is supported by the current findings. Since viewed on the microscale, the most prominent finding from this study is that the -OH groups influence the sticking coefficient. Nevertheless, if the desorption of ligands is encouraged by increasing the surface temperature (to the limit of the TMA precursor, but observed in this study at 573 K), the adsorbed molecules will reduce steric hindrance. As also shown in this study, the steric hindrance effects due to the -OH distribution on the surface significantly impact the ALD growth mode. The desired effect is that the surface needs to saturate quickly when the reactant diffuses to have a sharp profile front that will rapidly increase growth at fewer precursor doses but gain a steeper slope on the thickness. Therefore, avoiding populated -OH during the early stages of ALD assists with the rapid thickness growth. However, -OH groups at the surface lead to decreased sticking coefficient as they limit diffusion. \begin{table}
\begin{tabular}{c c c} \hline
**Method** & **Researchers** & \(\mathbf{S_{0}}\) \\ \hline Diffusion model, thickness profiles, lateral & [PERSON] et al., Ref. [35] & \(5.27\times 10^{-3}\) \\ high-aspect-ratio structure (LHAR) & [PERSON] et al., Ref. [17] & (2\(-\)7) \(\times\) 10\({}^{-3}\) \\ \hline LHAR, thickness profiles, 3D structures, experiments and Monte Carlo simulations & [PERSON] et al., Ref. [14] & \(2\times 10^{-2}\) \\ \hline LHAR, thickness profiles, 3D structures & [PERSON] et al., Ref. [36] & \(4\times 10^{-3}\) \\ \hline Molecular Dynamics (All-atom approach), thickness profiles, as [PERSON] et al. & Current study & \(4.257\times 10^{-3}\) \\ Ref ([PERSON] et al., 2019) & & \\ \hline \end{tabular}
\end{table} 
Table 2: Initial sticking coefficient of TMA during ALD of Al\({}_{2}\)O\({}_{3}\), determined from the thickness profiles at 300 \({}^{\circ}\)C substrate temperature. This study has shown that the initial sticking coefficient's influence promotes higher reactivity on the surface. The effect is best achieved from a stepper slope, which means the initial sticking coefficient of the TMA precursor will be higher \(>\)10\({}^{-3}\).