Improvement of Ferroelectricity in Ce-Doped Hf0.5Zr0.5O2 Thin Films

Abstract

At present, ion doping is a popular method typically used to regulate the ferroelectric properties of Hf0.5Zr0.5O2 films. In this work, Ce (cerium)–doped Hf0.5Zr0.5O2 (Ce: HZO) films on Pt/TiN/SiO2/Si substrates were prepared by the chemical solution deposition (CSD) method. The microstructure and ferroelectric properties of the Ce–doped HZO films were investigated in detail. The experimental results showed that the remanent polarization value of the films with cerium doping concentration of 7 mol% reached 17 μC/cm2, which is a significant improvement compared with the undoped Hf0.5Zr0.5O2 films. The reason for this may be the introduction of cerium ions, which can introduce a certain number of oxygen vacancies, thus stabilizing the formation of the orthogonal phase. Interestingly, the films were shown to be nearly fatigue free after 109 cycles of testing. These results demonstrate that cerium ion doping is an effective method for stabilizing the formation of the orthogonal phase of HZO films, and improving the ferroelectricity of HZO thin films.