Comprehensive Reliability Assessment of 32Gb (Hf,Zr)O<sub>2</sub>-Based Ferroelectric NVDRAM
D. P. Ettisserry, A. Visconti, M. Bonanomi, Riccardo Pazzocco, A. Locatelli, Alessandro Sebastiani, Ashonita Chavan, Matthew J. Hollander, G. Servalli, Alessandro Calderoni, Nirmal Ramaswamy
Abstract
NVDRAM is a 32Gb, dual layer 3D stacked, non-volatile (Hf,Zr)O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> -based 1T1C (1 Transistor � 1 Capacitor) ferroelectric memory technology. With high capacity, low cost and near-DRAM performance, NVDRAM is ideal for demanding Artificial Intelligence (AI) applications. For the first time, comprehensive reliability characterization and modeling of a very high density ferroelectric memory array is presented. We propose a new figure of merit called Effective Read Window as the relevant reliability metric for ferroelectric lifetime modeling. In addition to previously known mechanisms like imprint, fatigue and disturb, we characterize and model a unique failure mode associated with bipolar AC TDDB in ferroelectric memory arrays. Furthermore, we report a new degradation mechanism of frequency-dependent accelerated polarization loss in (Hf,Zr)O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> -based ferroelectric memory. Finally, we use the Effective Read Window framework to demonstrate reliability exceeding 10 years for NVDRAM.