This paper examined the application of ion bombardment (IB) and NH 3 plasma treatment (PT) techniques in fabricating a high-performance Si 3 N 4 charge storage layer. The IB technique can be used for creating numerous additional trap sites in the storage layer to enhance charge trapping efficiency and also causes changes in trap centroid location. In addition, the effect of centroid location on operation efficiency and reliability was investigated. Using gate-sensing and channel-sensing analysis, the changes in centroid location were demonstrated. In addition, the energy-level distribution of trap sites was clearly delineated by performing discharge-based multipulse analysis. The NH 3 PT technique can substantially passivate IB-induced shallow trap sites to increase data retention time. The influence of the NH 3 PT time on the memory characteristics of an IB-induced Si 3 N 4 sample was investigated. The optimal characteristics of an ion-bombarded and plasma-passivated Si 3 N 4 storage layer are presented. Compared with the conventional Si 3 N 4 storage layer, the optimal ion-bombarded and plasma-passivated Si 3 N 4 sample exhibited higher operation efficiency and superior reliability.