Reliable ferroelectricity down to cryogenic temperature in wake-up free Hf_0.5Zr_0.5O₂ thin films by thermal atomic layer deposition

Abstract

The performance and reliability of ferroelectric thin films at temperatures around a few Kelvin are critical for their application in cryo-electronics. In this work, TiN/Hf0.5Zr0.5O2/TiN capacitors that are free from the wake-up effect are investigated systematically from room temperature (300 K) to cryogenic temperature (30 K). We observe a consistent decrease in permittivity (ε r) and a progressive increase in coercive electric field (E c) as temperatures decrease. Our investigation reveals exceptional stability in the double remnant polarization (2P r) of our ferroelectric thin films across a wide temperature range. Specifically, at 30 K, a 2P r of 36 µC/cm2 under an applied electric field of 3.0 MV/cm is achieved. Moreover, we observed a reduced fatigue effect at 30 K in comparison to 300 K. The stable ferroelectric properties and endurance characteristics demonstrate the feasibility of utilizing HfO2 based ferroelectric thin films for cryo-electronics applications.