Variability and Reliability Study of Nano-Scale Hf_0.5Zr_0.5O₂ Ferroelectric Devices Using O₃ Treatment

Hf0.5Zr0.5O2 (HZO) faces challenges related to variability and reliability due to the instability of ferroelectric phase crystallization. This instability exacerbates reliability issues in HZO devices, especially as devices scale down to the nanometer level. In this study, we explore a method to tackle these issues in nano-scale ferroelectric HZO devices by directly analyzing switchable polarization. The devices used for the analysis are fabricated through different O-3 treatments, and the effects on variability and reliability are demonstrated. We calculate the switchable polarization values from the current responses to Positive Up Negative Down (PUND) voltage pulses. We then compare the device-to-device and cycle-to-cycle uniformity of 500 nm size devices and predict the variability of 100 nm size devices through phase distribution simulation. Additionally, we measure and compare imprint and retention properties using write and read delay tests at 85 degrees C. Our comprehensive analysis offers insights for fabricating reliable ferroelectric devices with superior uniformity and retention properties.