Optimizing Annealing Process for Ferroelectric Y-Doped HfO2 Thin Films by All-Inorganic Aqueous Precursor Solution

10 nm thick yttrium doped HfO2 (Y:HfO2) thin films are prepared on Si (100) substrates by the chemical solution deposition method using all-inorganic aqueous salt precursors. The influence of the annealing process, consisting of annealing temperature, holding time, and heating rate, on the crystalline structure and ferroelectric properties of thin films is investigated. Results show that the crystalline structure and ferroelectric properties of films exhibit a strong annealing process dependence. The monoclinic phase and asymmetric orthorhombic phase coexist in the films. The annealing process of the best ferroelectric behavior is obtained by using annealing temperature at 700 degrees C for 30 s with a heating rate of 30 degrees C s(-1) in N-2 atmosphere. The film exhibits lowest m-phase fraction of 17.9%, accompanied with the highest remanent polarization of 21.4 mu C cm(-2).