Ultrafast Switching Speed Demonstrated in Wafer-Scale Integration of Crystalline Undoped HfO2-Based Ferroelectrics

Hafnium oxide-based ferroelectric materials have been researched extensively for high-speed, low-power nonvolatile memory devices. However, doping HfO2 through atomic layer deposition (ALD) cycles primarily aims to enhance specific properties but also introduces challenges in balancing performance and reliability. Therefore, understanding the properties of intrinsic crystalline HfO2-based ferroelectric materials and developing undoped HfO2 ferroelectric devices with exceptional comprehensive properties are crucial. Here, we successfully fabricated well-engineered undoped HfO2 ferroelectric devices with high endurance (>1011 cycles), large grain size (>60 nm), and ultrahigh switching speed (∼1 ns). The results indicate that controlling the oxygen partial pressure can regulate the concentration of oxygen vacancies (VO), thereby stabilizing the ferroelectric phase. Finally, a comprehensive study of device variability is conducted, confirming a low device to device (D2D) variation. The outstanding comprehensive performance will enhance confidence in undoped HfO2 as a viable candidate for ferroelectrics in VLSI applications.