Modeling ALD Surface Reaction and Process Dynamics using Absolute Reaction Rate Theory

A physically based model of atomic layer deposition (ALD) surface reaction dynamics is developed and applied to alumina ALD with water and trimethylaluminum precursors. The time‐dependent growth surface composition is modeled by computing the equilibrium precursor adduct surface concentrations during each half‐reaction and the rate constants of the ligand exchange reactions using transition state theory. To describe the continuous cyclic operation of the deposition reaction system, a numerical procedure to discretize limit‐cycle solutions is developed and used to distinguish saturating growth per cycle (GPC) from non‐saturating (gpc) conditions. The transition between the two regimes is studied as a function of precursor partial pressure, exposure time, and temperature.