Saturation profile measurement of atomic layer deposited film by X-ray microanalysis on lateral high-aspect-ratio structure

Atomic layer deposition (ALD) of aluminum oxide thin films were applied on lateral high-aspect-ratio silicon test structures. The leading front of the film thickness profile is of interest, since it is related to deposition kinetics and provides information for ALD process development. A deposited profile was characterized using energy-dispersive electron probe X-ray microanalysis (ED-EPMA) and the results were analyzed using Monte Carlo simulation. A new procedure for obtaining relative film thickness profile from X-ray microanalysis data is described. From the obtained relative thickness profile, penetration depth of film at 50% of initial thickness and corresponding slope of thickness profile were determined at the saturation front. Comparison of the developed procedure was performed against independent measurements using optical reflectometry. ED-EPMA characterization of saturation profiles on lateral high-aspect-ratio test structures, supported by Monte Carlo simulation, is expected to prove useful tool for ALD process development.