New self-convergent programming method for multilevel AND flash memory

A new self-convergent programming method form multilevel AND-type flash mem ory is described to accurately control the dispersion of the programmed thr eshold voltage which is caused by the deviation of the applied voltage or t he FN tunneling current. Both channel initiated secondary electron injectio n (CHISEL) and avalanche hot electron injection (AHEI) Following the edge F N electron ejection can be used as the self-convergent programming techniqu es. However, CHISEL is shown to be better than AHEI for self-convergent ope ration due to faster speed, lower voltage, lower power consumption, and bet ter oxide reliability.