Improvements of Performance and Reliability for Metal–Oxide–Nitride–Oxide–Silicon Flash Memory With NO- or $\hbox {N}_{2}\hbox {O}$ -Grown Oxynitr

The characteristics of oxynitride thermally grown in either NO or N₂O ambient as a tunnel layer are investigated based on an Al/Al₂O₃/GdON/SiO_xN_y/Si structure. The physical thickness of each dielectric layer was measured and confirmed by multiwavelength ellipsometry and transmission electron microscopy. Experimental results reveal that better memory performances can be achieved for the metal-oxide-nitride-oxide-silicon (MONOS) device with NO-grown oxynitride as the tunnel layer, e.g., larger memory window, higher program/erase speed, better endurance, and retention characteristics, compared with devices with N₂O -grown oxynitride and conventional SiO₂ as the tunnel layer. The involved mechanisms lie in NO-nitridation-induced smaller hole barrier height, formation of more strong Si-N bonds at/near the oxynitride/Si interface due to more nitrogen incorporation in the tunnel layer. Therefore, the application of NO-grown oxynitride as tunnel layer is promising in advanced MONOS nonvolatile memory devices.