Characterization and Monte Carlo Analysis of Secondary Electrons Induced Program Disturb in a Buried Diffusion Bit-line SONOS Flash Memory

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 Vt 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.