The impact of work-function of metal gate and fixed oxide charge of high-k blocking dielectric on memory properties of NAND type charge trap flash memory devices

In this article, we report the impact of metal gate work function (QM) and fixed oxide charge (Qf) in blocking oxide on memory properties including erase and retention characteristics of charge trap flash (CTF) memory devices. For eliminating electron back tunneling (EBT) and hole back tunneling (HBT) trough blocking oxide during erase/program operation, metal gate with M of 5.15.7eV for high-K/SiN/S102 stack is necessary. Negative Qf in A1203 plays a crucial role in attaining lower erase state Vth while keeping thick tunnel oxide for good retention characteristics.