Electrical and Structural Properties of Metal-Oxide-Semiconductor (MOS) Devices with Pt/Ta₂O₅ Gate Stacks

Abstract

We fabricated metal-oxide-semiconductor (MOS) devices with Pt/Ta₂O₅ gate stacks and investigated their electrical and structural properties. As increasing RF magnetron sputter-deposition time of Ta₂O₅ film, the values of equivalent oxide thickness (EOT) and flat band voltage (V_FB) increase whilst the density of interfacial trap (D_it) gradually decreases. The effective metal work function (Φ_m,eff) of Pt metal gate, extracted from the relations of EOT versus V_FB are calculated to be ∼5.29eV, implying that Fermi-level pinning in Ta₂O₅ gate dielectric is insignificant.