High permittivity thin film nanolaminates

Abstract

Thin (∼10 nm) films comprising of Ta2O5–HfO2, Ta2O5–ZrO2, and ZrO2–HfO2 nanolaminates were deposited and characterized for possible gate dielectric applications. These films were deposited on silicon substrates using atomic layer deposition. The dielectric constants of these films were in 12–14 range and the leakage currents in 2.6×10−8–4.2×10−7 A/cm2 range at 1 MV/cm electric field. It was found that as these films were made thinner, the value of their dielectric constant dropped compared to their bulk values. The dominant leakage current mechanism at low electric fields was determined to be Schottky emission, whereas Poole–Frenkel emission dominated at higher fields.