Characterization and Monte Carlo analysis of secondary electrons induced program disturb in a buried diffusion bit-line SONOS flash memory

Abstract

A new program disturb in a buried diffusion bit-line SONOS array is observed as a bit-line width is reduced. A multi-step Monte Carlo simulation is performed to explore the disturb mechanism. We find that the V, shift of a disturbed cell is attributed to impact ionization-generated secondary electrons in a neighboring cell when it is in programming. The effects of substrate bias, bit-line dimension and pocket implant on the program disturb are characterized and evaluated by a Monte Carlo simulation.