Modelling the Deposition of High-k Dielectric Films by First Principles

Considerable interest is focussed on high-k dielectrics as replacements for the gate oxide in future MOSFETs. Atomic Layer Deposition (ALD) is the method of choice to produce conformal thin films for the gate dielectric, but a deeper understanding of this method is needed for process optimisation. For ALD of alumina, we use first principles density functional (DFT) calculations to describe the surface intermediates and pathways of precursor adsorption/decomposition at the atomic scale, yielding quantitative reaction energetics. This reveals the intrinsic limits on ALD growth rate as a function of OH coverage.