Towards an ideal high-κ HfO-ZrO-based dielectric

The existence of a morphotropic phase boundary (MPB) inside HfO 2 -ZrO 2 solid solution thin films has been predicted; if it exists, it provides a new path toward an ideal silicon-compatible dielectric. Herein, we investigate the structural evolution along with the dielectric and ferroelectric behaviors of differently designed HfO 2 -ZrO 2 thin films to engineer the density of the MPB inside the film structure and consequently, enhance the dielectric properties. Polarization vs. electric field ( P - E ) measurements of Hf 0.25 Zr 0.75 O 2 thin films reveal ferroelectric (FE)-antiferroelectric (AFE) characteristics. For this composition, the dielectric constant r is higher than those of FE Hf 0.5 Zr 0.5 O 2 and AFE ZrO 2 thin films; the difference is attributed to the formation of the MPB. To increase the density of the MPB and subsequently the dielectric properties, 10 nm Hf 0.5 Zr 0.5 O 2 (FE)/ZrO 2 (AFE) nanolaminates were prepared with different lamina thicknesses t L . The coexistence of FE and AFE properties was confirmed by structural characterization studies and P - E measurements. The thinnest layered nanolaminate ( t L = 6 Å) showed the strongest dielectric constant r ∼ 60 under a small signal ac electric field of ∼50 kV cm −1 ; this is the highest r so far observed in HfO 2 -ZrO 2 thin films. This behavior was attributed to the formation of an MPB near FE/AFE interfaces. The new design provides a promising approach to achieve an ideal high-κ CMOS-compatible device for the current electronic industry. Dielectric properties are improved by fabrication of a Ferroelectric Hf 0.5 Zr 0.5 O 2 /Antiferroelectric ZrO 2 nanolaminate structure. The new design increases the density of morphotropic phase boundary, which consequently enhances the dielectric constant.