Comparison between Al2O3 thin films grown by ALD using H2O or O3 as oxidant source

Alumina (Al₂O₃) thin films have been deposited on silicon substrates by atomic layer deposition at 200°C using TMA as Al precursor and H₂O or O₃ as oxygen precursor. The growth rate has been found to be lower for ozone-based processes as compared to H₂O. The electrical characterization of the deposited layers has shown that when using O₃ the films exhibit larger defect densities as compared to those grown using H₂O, although these show larger trapping. A post deposition anneal process at 650°C has been shown to lower the defect densities, being this annealing more efficient for O₃-grown layers. The effect of post-metallization annealing in forming gas is also investigated.