Investigation on the effect of tunnel oxide nitridation to threshold voltage instability mechanisms of nanoscale CT NVM

• TON process modulates Vt instability mechanism of nanoscale nitride based CT NVM.
• Increasing bake temperature on non-nitrided CT NVM resulted in uniform Vt shift.
• Increasing bake temperature on nitrided CT NVM heals tunnel oxide defects.
• Tail bits generation on nitrided CT NVM is attributed to TAT mechanism.
• Increasing electric field across ONO will increase tail bits on nitrided CT NVM.

In this study, the effect of tunnel oxide nitridation (TON) on the dynamics of charge loss (CL) mechanisms of nanoscale charge trapping (CT) non-volatile memory (NVM) is investigated. To the best knowledge of the authors, for the first time, the change in the dominant CL mechanism is reported. The Vt distribution was found to change from uniform to bi-modal distribution as a result of the effect of TON. The effect of the enhanced internal electric field across Oxide–Nitride–Oxide (ONO) stack of nitrided nanoscale CT NVM was studied by designing a set of Program Verify (PV) levels settings. This effect of enhanced electric field was found to exacerbate the dominant room temperature (RT) CL mechanism which manifests in higher bi-modal Vt distribution shift. Physical interpretations and reliability implications of the change in dominant CL mechanisms and the effect of the enhanced internal electric field to RTCL mechanism observed due to TON are deliberated.