Mist-CVD-derived Hf0.55Zr0.45O2 ferroelectric thin films post-annealed by rapid thermal annealing

Abstract

We have newly applied Rapid Thermal Annealing (RTA) for the post-annealing of mist chemical-vapor-deposition (CVD)-derived Hf1−xZrxO2 (HZO) thin films. A ferroelectric polarization-electric field (P–E) curve was confirmed typically with noticeable polarization reversal currents. These ferroelectric properties of the HZO thin films provided quantitative estimation for Pr and Ec of ∼20 µC/cm2 and 1–1.5 MV/cm, respectively, compared to those reported from other growth methods, such as atomic-layer-deposition (ALD). It was revealed that the background leakage should be further reduced in a mist-CVD HZO film compared to those by ALD recently reported. The origin of the leakage was strongly related to the oxygen vacancy (Vo) generated in the film and near the HZO/bottom electrode interface. Nonetheless, it was found effective to use atmospheric pressure in air or oxygen in the post-RTA process for reducing leakage. In general, endurance behaviors for the mist-CVD HZO film revealed similar to those for samples prepared by other methods for both “wake-up” and “fatigue” phenomena, showing that the mist-CVD HZO film endured up to 2 × 109 counts. Finally, we expect that the mist-CVD HZO thin film would become a candidate for fabricating large-scale integration-oriented ferroelectric devices due to the intrinsic merits of the method.