A density functional theory study on the reactions of chlorine loss in ZrO2 thin films by atomic-layer deposition

The chlorine loss reactions of ZrO2 thin films of atomic layer deposition on the hydroxylated silicon surface have been studied by the density functional theory. Fourteen possible pathways are designed to investigate the detailed chlorine loss reaction mechanism based on the two-dimer trench silicon cluster model. Experiment shows that HCl self-elimination is the dominant reaction pathway at the low temperatures, and that hydrolysis is the dominant pathway at elevated temperatures for the second chlorine loss reaction. However, our calculations show that raising temperature would not result in HCl self-elimination reaction to be unfavorable. Therefore, the decrease of the number of hydroxyls is the possible reason. In addition, for the four chlorines loss, the reactions on the two-dimer cluster across the trench are compared with those on the same dimer cluster from the viewpoint of energy.