ABSTRACTMetal as floating gate (FG) in combination with high-k dielectrics has been seen as a possible solution to continue the scaling of NAND flash technology node beyond 2X nm. In this work, metal FG memory device with high-k engineered Inter-Gate-Dielectric (IGD) and/or tunneling layer (TL) was detailed investigated. It presents improved performance with lower operation voltage as well as faster speed, compared to control samples. Furthermore, improvement of long-term data retention is observed for the high-k engineered devices, proving that the introduction of engineered IGD and/or TL is a promising solution for further performance improvement of full metal FG memory device.