This brief presents a new nitridation process on floating poly-Si gate to improve the quality of both tunneling oxide and interpoly-oxide of nonvolatile memories. Three types of poly-Si for a floating gate have been investigated. We found in-situ doped poly-Si shows the best performance in terms of breakdown field, charge-to-breakdown (QBD) and trapping rate. The Q BD of interpoly-oxide can be reached as high as 35 C/cm2. This scheme is very promising for nonvolatile memory devices.