Excellent ferroelectricity of 50 nm-thick doped HfO2 thin films induced by annealing with a rapid-heating-temperature process

• Main Authors: Zhiyong Quan, Meimei Wang, Xiao Zhang, Huihui Liu, Wei Zhang, Xiaohong Xu
• Format: Article
• Language: English
• Published: AIP Publishing LLC 2020-08-01
• Series: AIP Advances
• Online Access: http://dx.doi.org/10.1063/5.0013511

The ferroelectric HfO2 thin film has attracted a lot of research interest due to being Pb free and its excellent compatibility with the Si-based semiconductor process. However, methods to obtain thicker HfO2 thin films with strong ferroelectricity have yet to be explored. In this work, a 50 nm-thick La-doped HfO2 thin film was prepared using pulsed laser deposition, and significant room temperature ferroelectricity with a remnant polarization (Pr) of 27 µC/cm2 was achieved through annealing in N2 with a rapid-heating-temperature process. The ferroelectricity is mainly related to the increase in the content of the (002)-oriented orthogonal phase formed by the rapid-heating-temperature treatment. Furthermore, this special annealing process was verified in a 50 nm-thick Tm-doped HfO2 film, and the Pr of 48 µC/cm2 was observed. This value is the highest value reported so far in doped HfO2 films with a thickness of 50 nm or greater. These results provide a new approach to prepare thicker ferroelectric HfO2-based thin films.