Hydrogen distribution in oxide-nitride-oxide stacks and correlation with data retention of MONOS memories

Abstract

We demonstrate that hydrogen (H) atom penetration into the bottom oxide (BTO) of ONO stacks degrades the retention reliability of MONOS memory. We observe that post-nitride (SiN) N2-annealing improves the retention through a suppression of the H atom diffusion in ONO stacks. Nuclear reaction analysis revealed the presence of an ultra thin H-storage layer in the top oxide/SiN interface, which can effectively shield the BTO from H diffusion, and in turn provides H species resistant against energetic electron damage.