Surface Reaction Mechanisms during Plasma-Assisted Atomic Layer Deposition of Titanium Dioxide

Abstract

We have investigated the surface reaction mechanisms during the O2-plasma-assisted atomic layer deposition (ALD) of TiO2 from titanium tetraisopropoxide using in situ attenuated total reflection Fourier transform infrared spectroscopy. We show that the reaction mechanism involves a combination of O3- and H2O-based ALD chemistries, where both metal carbonates and surface hydroxyl groups are the reactive site for chemisorption of the metal precursor. The TiO2 films have anatase crystal structure at 150 °C with a growth per cycle of ∼0.83 Å, which is much higher than that for amorphous films.