Effects of doping concentration and annealing temperatures on the ferroelectric memory properties of yttrium doped HfO<sub>2</sub>
Haiyan Chen, Hang Luo, Xi Yuan, Junliang Yang, Dou Zhang
Abstract
Abstract HfO 2 has been widely studied in nonvolatile memories owing to its advantages including wide bandgap, superior ferroelectricity, low power and high density. Herein, yttrium doped hafnium (Y: HfO 2 ) films were fabricated on Si (100) substrate by chemical solution deposition method. Effect of Y contents on the structural and electrical performance of Y: HfO 2 ferroelectric films was carefully investigated in the range of 0–10 mol%. Results revealed that Y: HfO 2 was crystallized from m-phase to c/o-phase with the increase of Y contents which exhibited a strong dependence on the concentrations of oxygen vacancies. 7 mol% Y: HfO 2 achieved the highest remnant polarization of 23.37 μ C cm −2 after being annealed at 700 °C for 60 s in O 2 atmosphere. Significant domain switching patterns could be written by piezoelectric force microscope indicating the good ferroelectricity in 7 mol% Y: HfO 2 . Lower and higher annealing temperatures were not beneficial for the improvement of ferroelectricity due to the large leakage current and over-crystallization, respectively. This work would provide useful guidance for HfO 2 -based films in future memories with great potential.