Suppression of lateral charge redistribution using advanced impurity trap memory for improving high temperature retention

For retention improvement in scaled SONOS-type nonvolatile memory, deep traps with controllable density were formed by adding metal impurities into gate oxide. We find that Ti additives create deep traps in silicon dioxide, with high electron capture efficiency Charge storage node changed from TiO₂ floating-gate (15Aring) to nano-crystals (3Aring), and further to atomic-sized traps (0.4Aring) by decreasing Ti amount. Discrete atomic-sized traps successfully suppressed lateral charge redistribution, improving retention at 150degC