Fe-RAM has received much interest in recent years for emerging memory and neuromorphic applications. In particular, recent findings of ferroelectric properties utilizing HfO2 have excited the scientific community as new possibility of scaling.

At the IEDM 2021, we shared the results of FE-RAM in 3D capacitor structures in a commercial production scale. The feasibility study of the 1Xnm node FE-RAM was carried out by combining the new memory technology and the mature process technology and integration of SK hynix. As a result, the world’s first 1Xnm half-pitch FE-RAM with 8Gb density was fabricated, and its operation was confirmed.

The conventional FE-RAM maximizes 2Pr (Pr: Remnant Polarization) by adjusting the capacitor plate voltage according to the data. In this study, despite using a fixed capacitor plate voltage, we showed the memory operation even at a low voltage of ±0.6V by using the pinched hysteresis of 5nm-thick ultra-thin HZO. We measured the switching speed by changing the write time from 5ns to 80ns. 70% of the total polarization can be switched within 20ns tWR (like DRAM), and the remaining 30% responds to a wide range of write time between 20 and 80ns. To improve the switching speed, it is necessary to reduce bulk defects or design schemes such as Vcore overdrive. 

It is also true that further research is needed to improve 2Pr and speed up switching to be able to manufacture high density, high speed, and low power FE-RAM, which we continue to investigate. We hope this study will help the scientific community by providing a meaningful foundation for scaled Fe-RAM for future memory applications. 

The publication: Link