Improvement of Interpoly Dielectric Characteristics by Plasma Nitridation and Oxidation for Future nand Flash Memory

In this letter, plasma nitridation and oxidation on interpoly dielectric (IPD; SiO
₂
-SiN-SiO
₂
) for cell programming speed and reliabilities are investigated. Nitrided top oxide with N
₂
plasma shows excellent physical and electrical properties in terms of edge profile on IPD and fast programming voltage. However, plasma nitridation on a floating gate suffers from data retention problems that result from nitridelike residue along the word line. A method to densify and reoxidize bottom oxide with O
₂
plasma oxidation is proposed for leakage path inhibition and data retention improvement.