Excellent Reliability and High-Speed Antiferroelectric HfZrO2 Tunnel Junction by a High-Pressure Annealing Process and Built-In Bias Engineering

• Published in: ACS applied materials & interfaces 2020-12, Vol.12 (51), p.57539-57546
• Main Authors: Goh, Youngin, Hwang, Junghyeon, Jeon, Sanghun
• Format: Article
• Language: English
• Subjects: Surfaces, Interfaces, and Applications
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c15091

Hafnia-based ferroelectric tunnel junctions (FTJs) have great potential for use in logic in nonvolatile memory because of their complementary metal–oxide–semiconductor process compatibility, low power consumption, high scalability, and nondestructive readout. However, typically, ferroelectrics have a depolarization field, resulting in poor endurance owing to the early dielectric breakdown. Herein, an outstandingly reliable and high-speed antiferroelectric HfZrO tunnel junction (AFTJ) is probed to understand whether it is a promising candidate for next-generation nonvolatile memory applications. High-reliability AFTJ can be explained by less charge injection due to the low depolarized field. The formation of two stable nonvolatile states, even with antiferroelectric materials, is possible if asymmetric work function electrodes and fixed oxide charges are employed, generating a built-in bias and shifting the polarization–voltage curve. In addition, via high-pressure annealing, a critical voltage that determines the transition from the t-phase to the o-phase is effectively reduced (22%). The AFTJ shows a higher endurance property (>109 cycles) and faster switching speed (