A study of hot-hole injection during programming drain disturb in flash memories

Program disturbs in NOR-type Flash arrays significantly degrade the tunnel oxide by hot-hole injection (HHI) induced by band-to-band tunneling at the drain overlap. This paper provides a comprehensive experimental and modeling analysis of HHI in Flash memories under program-disturb conditions. Carrier-separation measurements on arrays of Flash memories with contacted floating-gate (FG) allows for a direct investigation of hole-initiated impact ionization and HHI. A Monte Carlo (MC) model is used to simulate carrier multiplication and injection into the FG. After validating the MC model against experimental data for both secondary electron generation and HHI, the model is used to provide further insight into the hole-injection mechanism.