Novel ZrO2/Si3N4 Dual Charge Storage Layer to Form Step-Up Potential Wells for Highly Reliable Multi-Level Cell Application

A novel ZrO₂/Si₃N₄ dual charge storage layer (DCSL) has been proposed for highly reliable multi-level cell (MLC) application. Separated charge storage and step-up potential well have been resulted from the ZrO₂/Si₃N₄ DCSL. Threshold voltage (V_th) levels are controlled by the charge storage capacity of each CSL, instead of the amount of charge injection, making a superior multi-level Vth control possible. Negligible V_th, offsets (<0.2V) are maintained throughout the 10⁵ programming/erasing (P/E) cycles, demonstrating a significantly improved endurance reliability compared to NROM-type MLC.