Improvement of ferroelectricity and endurance in Sr doped Hf0.5Zr0.5O2 films

The doping of Hf0.5Zr0.5O2 has attracted increasing attention because of the further regulation of structure and ferroelectric properties. Here, Sr doped Hf0.5Zr0.5O2 (Sr:HZO) ferroelectric films have been prepared by chemical solution deposition on Pt/Ti/SiO2/Si substrate, and the effect of Sr doping on the structure and ferroelectric properties of Sr:HZO films was investigated. It is observed that Sr doping can further promote the formation of ferroelectric orthorhombic phase at low content (≤0.50%), inducing the enhancement of ferroelectricity. And the optimal ferroelectricity with remanent polarization of 14.63 μC/cm2 and coercive field of 1.08 MV/cm is achieved in the 0.50% Sr doped HZO film. The decrease in leakage current density with increasing Sr content is observed, which is mainly ascribed to the reduction of grain boundaries caused by the increase of grain size. Most significantly, Sr doping induces an improvement in the endurance, and a good endurance of 109 cycles without breakdown is achieved in the 0.50% Sr doped sample. These findings indicate that Sr is a potential candidate dopant for improving the structure and ferroelectric properties of HZO films.