Reliability Study of 1T1C FeRAM Arrays With Hf_0.5Zr_0.5O₂ Thickness Scaling

Abstract

We have reported that film thickness scaling of ferroelectric Hf0.5Zr0.5O2(HZO) allows hafnium-based one- transistor and one-capacitor (1T1C) ferroelectric random-access memory (FeRAM) to obtain higher cycling tolerance for hard breakdown with lower voltage operation in prior reports. This paper is an extension of the previous works including a review of recent works on FeRAM-related devices from a film thickness scaling point of view. We experimentally verified the cycling tolerance advantage of film thickness scaling by 1T1C FeRAM array with different HZO thicknesses of 8 nm and 10 nm using different small capacitors areas (0.20, 0.40, and $1.00~\mu\text{m}^{2}$ ) at practical operation conditions for the first time, demonstrating higher reliability at the 8-nm sample with smaller capacitance area. To support the result, time zero dielectric breakdown (TZDB) and time dependent dielectric breakdown (TDDB) were conducted for both 8-nm and 10a-nm samples.

Keywords

• Capacitor
• ferroelectric random-access memory
• hafnium oxide
• thickness scaling
• zirconium oxide