Effect of fabrication parameters on the ferroelectricity of hafnium zirconium oxide films: A statistical study.

Ferroelectricity in hafnium zirconium oxide (Hf_{1 − x}Zr_xO₂) and the factors that impact it have been a popular research topic since its discovery in 2011. Although the general trends are known, the interactions between fabrication parameters and their effect on the ferroelectricity of Hf_{1 − x}Zr_xO₂ require further investigation. In this paper, we present a statistical study and a model that relates Zr concentration (x), film thickness (t_f), and annealing temperature (T_a) with the remanent polarization (P_r) in tungsten (W)-capped Hf_{1 − x}Zr_xO₂. This work involved the fabrication and characterization of 36 samples containing multiple sets of metal-ferroelectric-metal capacitors while varying x (0.26, 0.48, and 0.57), t_f (10 and 19 nm), and T_a (300, 400, 500, and 600 ° C). In addition to the well-understood effects of x and T_a on the ferroelectricity of Hf_{1 − x}Zr_xO₂, the statistical analysis showed that thicker Hf_{1 − x}Zr_xO₂ films or films with higher x require lower T_a to crystallize and demonstrated that there is no statistical difference between samples annealed to 500 and 600 ° C, thus suggesting that most films fully crystallize with T_a ∼ 500 ° C for 60 s. Our model explains 95% of the variability in the P_r data for the films fabricated, presents the estimates of the phase composition of the film, and provides a starting point for selecting fabrication parameters when a specific P_r is desired. [ABSTRACT FROM AUTHOR]