Ultrahigh dielectric permittivity in Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> thin-film capacitors.

Zhang, Wen Di; Song, Zi Zheng; Tang, Shu Qi; Wei, Jin Chen; Cheng, Yan; Li, Bing; Chen, Shi You; Chen, Zi Bin et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

The ever-shrinking electrostatic capacitor, which is capable of storing substantial quantities of electrical charge, has found widespread applications in high-storage-density dynamic random access memory and energy-efficient complementary metal-oxide-semiconductor devices. Despite the high energy storage densities (133-152 J/cm<sup>3</sup>) and efficiencies (75-90%) that have been realized using relaxor ferroelectric thick films, low-permittivity interfacial layers in the ultrathin films have caused the overall permittivity to be one to two orders of magnitude lower than expected. However, innovative use of complementary metal-oxide-semiconductor-compatible HfO<sub>2</sub>-based materials with high permittivities (~52) could enable integration of these capacitors into few-nanometre-scale devices. This study reports an ultrahigh dielectric permittivity of 921, stored charge density of 349 μC/cm<sup>2</sup>, and energy density of 584 J/cm<sup>3</sup> with nearly 100% efficiency within near-edge plasma-treated Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> thin-film capacitors when the Hf-based material's ferroelectricity disappears suddenly after polarization fatigue. The ultrahigh dielectric permittivity originates from a distorted orthorhombic phase with ordered oxygen vacancies that enables high-density integration of extremely scaled logic and memory devices for low-voltage applications.