Effects of Lateral Charge Spreading on the Reliability of TANOS (TaN/AlO/SiN/Oxide/Si) NAND Flash Memory

It was found that the charge loss behavior of TANOS (TaN-Al₂O₃-nitride-oxide-silicon) cells for NAND flash memory application is highly dependent on the gate structures for the first time. The gate structures with trap layers remained on source and drain regions showed increased charge loss compared to the one with trap layers separated between different gate lines. The improvement by removing the trap layers between gate lines suggests that the lateral charge spreading via trap layers from the programmed cells to the adjacent erased cells contributes to the charge loss of the TANOS cells.