Mechanism of drain disturb in SONOS flash EEPROMs

Abstract

We investigate the mechanism of drain disturb in SONOS flash memory cells. Our results show that drain disturb can be a serious concern in a programmed state and is caused by injection of holes from the substrate into the nitride. We identify the key factors responsible for this to be band-to-band tunneling at the drain junction and impact ionization of the channel leakage current.