High reliability ultrathin interpolyoxynitride dielectrics prepared by N₂O plasma annealing

This work addresses the preparation of ultrathin (effective oxide thickness, 42 Å) interpoly-oxynitride (SiO_xN_y) films by annealing thin nitride films with high density N₂O plasma and N₂O rapid thermal annealing. The proposed oxynitride dielectrics formed using N₂O plasma annealing exhibited low gate leakage current, high breakdown electric field, long ten-year lifetime, and large effective barrier height. These superior properties can be attributed to the high concentration of oxygen incorporated in the poly-II/nitride interface and a reduction of the trap density of the interpoly-oxynitride films. The dielectric is a suitable substitute for the inter-polyoxide of electrically-erasable programmable read only memory.