Chemisorption of tetrakis(dimethylamino)zirconium on zirconium oxide: Density functional theory study

Abstract

We investigated the chemisorption mechanism of tetrakis(dimethylamino)zirconium, Zr(NMe2)4, on zirconium oxide (ZrO2) to understand the first half-reaction of the atomic layer deposition (ALD) process of ZrO2 films. A hydroxylated monoclinic ZrO2 (-111) 2×2 slab model was constructed, and the surface hydroxyl group density was optimized. The obtained density through the optimization procedure was 4.5 nm−2, which closely matches the value reported in the literature. Then, the sequential ligand exchange reactions involving a Zr(NMe2)4 molecule and the –OH terminated ZrO2 surface were simulated. The first two reactions had low activation energies of 0.19 and 0.24 eV and were exothermic. Conversely, the third reaction was endothermic. Therefore, the resulting surface species after chemisorption was expected to be O2Zr(NMe2)2*, which is consistent with in situ analyses in the literature.