Towards modeling of ZrO2 atomic layer deposition at reactor scale based on experimental kinetic approximation

In this study, the growth kinetics of ZrO2 via the atomic layer deposition (ALD) using a mixed alkylamidocyclopentadienyl zirconium precursor are proposed based on experimental data to evaluate the film growth behavior using reactor-scale simulation. In the ALD process, the hydroxyl concentration on the targeted surface govern the saturated growth per cycle values. However, we found that the bulkiness of remaining ligands on adsorbed species hinders the adsorption of Cp-Zr molecules. Considering this phenomenon, we proposed a kinetic model by calculating the energetic terms to quantify the steric hindrance effect of the first elementary surface reaction of CpZr(N(CH3)2)3 precursor (Cp-Zr), which enables the film growth prediction with the reactor-scale computational fluid dynamic (CFD) model. According to the experimental ALD process, the film growth was found to be influenced by the steric hindrance factor, especially at the temperature range from 150 degrees C to 250 degrees C, but the hindrance effect decreases with increasing temperature and disappears at 300 degrees C. The effective activation energy of the adsorption of Cp-Zr molecules on Si substrate was estimated to be 0.175 eV. Further understanding of the kinetic of ZrO2 deposition in this study is estimated to contribute to the optimization of the high-k metal oxides ALD deposition processes.

Automated summary

This study proposes a growth kinetics model for ZrO2 in atomic layer deposition (ALD) using a mixed alkylamidocyclopentadienyl zirconium precursor. The model is based on experimental data and evaluates film growth behavior using reactor-scale simulation. The study finds that the adsorption of Cp-Zr molecules is hindered by the bulkiness of remaining ligands on adsorbed species. The hindrance effect is significant at temperatures between 150°C and 250°C, but decreases with increasing temperature and disappears at 300°C. The research provides valuable insights for optimizing ALD deposition processes of high-k metal oxides.