Selectivity dependence of atomic layer deposited manganese oxide on the precursor ligands on platinum facets

Selective atomic layer deposition shows a great perspective on the downscaling manufacturing of nanoelectronics with high precision. The interaction between Mn precursors and Pt terrace, (100), and (111) facets is investigated by density functional theory and microkinetic modeling to reveal the effect of the ligands of the precursors on MnO_x selective growth on the Pt facets. MnCl₂ and MnCp₂ have preferential deposition on the Pt terrace and (100) over (111), while Mn(acac)₂ does not show obvious selectivity on the three pristine Pt facets due to the extremely strong adsorption energies. It is found that the adsorption energies of the Mn precursors exhibit size dependence mainly due to the van der Waals interaction. The increase in the number of methyl substituents of Cp-derivate precursors enlarges the decomposition energy barrier of the precursor on (100) due to the steric hindrance, which weakens the selectivity between (111) and (100) facets. It is found that the oxygen groups on these facets accelerate the decomposition of the precursors, which diminishes the selectivity of the precursors on the three Pt facets. While the surface hydroxyl groups significantly weaken the adsorption of Mn(acac)₂, it exhibits preferential deposition on hydroxylated Pt (111) among the three facets. Our work highlights the group effect on adsorption, reaction kinetics, and the selective growth of Mn precursors on Pt facets, which provides important guidance to screen precursors to achieve selective deposition of metal oxides on differentiated metal surfaces.