Enhancing Performance and Reliability of FeNAND Hybrid Memory via a 2D-WS₂ Layer for Charge Trapping and...

Ferroelectric NAND (FeNAND) devices utilizing ferroelectric hafnia thin films have emerged as promising candidates for future V-NAND applications. Hybrid memories integrating conventional charge trap layers into FeNAND structures have been extensively explored for their enhanced electrical performance. However, crystallization issues in the ferroelectric layer remain a critical barrier, despite achieving sufficient memory windows. Here, we present a FeNAND hybrid memory incorporating a multifunctional 2D-WS₂ layer to simultaneously improve performance and reliability. Positioned adjacent to the ferroelectric Hf_1-xZr_xO₂ (HZO) layer, the 2D-WS₂ layer facilitates high-quality crystallization of the HZO, thereby enhancing and stabilizing its ferroelectricity. In addition, it serves as an efficient charge trap layer, resulting in a substantially increased memory window and improved retention. The 2D-WS₂ layer was deposited via atmospheric-pressure plasma-enhanced chemical vapor deposition and characterized through structural analysis. Polarization measurements revealed more than a 2-fold enhancement, and electrical characterization of FeNAND devices with an IGZO channel demonstrated a significantly enlarged memory window of 7.24 V. The hybrid memory also exhibited multilevel cell operation enabled by the combined modulation of polarization and trapped charge. Furthermore, it achieved outstanding endurance beyond 10⁸ cycles and stable retention, surpassing the conventional reliability limits of FeNAND architectures. Uniformity improvements were verified through a phase distribution model and hybrid memory operation simulations. This work offers a practical pathway toward realizing viable HZO-based FeNAND technology for future V-NAND applications.