Ion Bombardment during Plasma-Assisted Atomic Layer Deposition

The presence and influence of ions in several reactor configurations used for plasma-assisted atomic layer deposition (ALD) are discussed. It is shown that the ion energies are often moderate or even negligible in direct plasma and remote plasma ALD reactors under processing conditions typically employed. Plasma-induced damage by ion bombardment is therefore not a major issue during most processes. It has furthermore been demonstrated that ion energies can be enhanced using substrate biasing, which can be used to tailor the material properties as demonstrated for several metal-oxides.