Stabilization of the cubic phase of HfO2 by Y addition in films grown by metal organic chemical vapor deposition

Abstract

Addition of yttrium in HfO2 thin films prepared on silicon by metal organic chemical vapor deposition is investigated in a wide compositional range (2.0–99.5at.%). The cubic structure of HfO2 is stabilized for 6.5at.%. The permittivity is maximum for yttrium content of 6.5–10at.%; in this range, the effective permittivity, which results from the contribution of both the cubic phase and silicate phase, is of 22. These films exhibit low leakage current density (5×10−7A∕cm2 at −1V for a 6.4nm film). The cubic phase is stable upon postdeposition high temperature annealing at 900°C under NH3.