Bottom Nitridation Engineering of Multi-Nitridation ONO Interpoly Dielectric for Highly Reliable and High Performance NAND Flash Memory

Abstract

The various methods of Multi-Nitridation ONO to improve NAND Flash memory have been demonstrated in this paper. Excellent cell performance and reliability are obtained compared to convention ONO: (1) 1.9V program voltage reduction owing to 23A EOT (equivalant oxide thickness ) reduction (2) More than 20% tighter cell Vt distribution width and 30% narrower Vth shift after 10K cycling can be achieved by supressing ONO bird's beak encroachment of gate re-oxidation by Floating Gate (FG) / top oxide nitridation. MN-ONO is a promising technology for high density NAND Flash beyond 40nm generation.