Toward Atomic-Scale Patterned Atomic Layer Deposition: Reactions Of Al2o3 Precursors On A Si(001) Surface With Mixed Functionalizations

In this paper, we use density functional theory (DFT) calculations to investigate the initial surface reactions involved in the atomic layer deposition (ALD) of Al2O3 from H2O and Al(CH3)(3) (trimethylaluminum, TMA) molecular precursors on the Si(001)-(2X1) reconstructed surface with different chemical terminations. Our results for the kinetic barriers and adsorption energies of both Al and oxygen precursors along different reaction pathways show the dependence of the ALD nucleation rate on the surface defects (Si dangling bonds or dimer trench) and how it can be modified with suitable p-doping. Finally, our ab initio thermodynamics study clearly determines the relation between typical ALD working conditions and the different chemical functionalizations of the Si(001) surface with the growth properties of Al2O3 nanofilms.