A novel multi-level program method for 4-bit per cell operation in SONOS memory

A novel program method is proposed for multi-level programming with a low-voltage step in a conventional SONOS structure. This method uses junction avalanche hot carriers for charge storage in the nitride layer. A multi-level storage is easily obtained by using a low-voltage step of 0.1 V at each level of the three programmed states along with a fast program time of 1 ㎲.