A theoretical study on the surface reaction of tetrakis(dimethylamino)titanium on titanium oxide

Abstract

Tetrakis(dimethylamino)-titanium (TDMAT, Ti(NMe₂)₄) has been used for the low-temperature atomic layer deposition (ALD) process of titanium oxide (TiO₂) films. In this study, the chemisorption of TDMAT on a titanium oxide surface using a slab model was simulated by density functional theory (DFT) calculation. We calculated the activation energy for the chemisorption and predicted the final chemisorbed species. A TiO₂ slab model was constructed with the optimized number of –OH surface groups. Three serial ligand exchange reactions between a TDMAT molecule and the TiO₂ slab were exothermic with low activation energies of 0.16–0.46 eV, which can explain the low processing temperatures of the ALD TiO₂ processes. Our DFT calculation showed that three NMe₂ ligands of TDMAT would be released and the surface species of –TiNMe₂ would be formed, which is in good agreement with the experimental observation in the literature.