Enhanced Capacitive Memory Window by Improving Remnant Polarization in Ferroelectric Capacitors for Non-Destructive Read

Abstract

The unique concept of a non-volatile capacitive memory window (CMW) in ferroelectric (FE) capacitors (FeCAP) allows for a non-destructive read operation (NDRO). NDRO decouples the read- from the write-endurance which is ideal for random access memory and compute-in-memory applications. However, the optimal strategy to further improve the CMW remains uncertain. In this work, we first identify potential pathways to improve the CMW by studying the dependence of the relative dielectric permittivity ( $\epsilon _{\text {r}}$ ) of a FE on the remnant polarization ( ${P}_{\text {R}}$ ) and coercive field ( ${E} _{\text {C}}$ ). Results show that a FE stack having a higher ${P}_{\text {R}}$ and/or a lower ${E}_{\text {C}}$ leads to an improved $\epsilon _{\text {r}}$ and CMW for a given read-bias. Next, we experimentally demonstrate this and show that a trilayer FeCAP with an enhanced $2{P}_{\text {R}}$ achieves a high CMW $_{\epsilon }$ of ~20, which is ~1.5x higher than earlier best. Finally, we demonstrate a pulse-based NDRO confirming a robust 1.5x enhancement in CMW even after $10^{{11}}$ NDRO cycles.