NONVOLATILE SEMICONDUCTOR MEMORY DEVICE, MANUFACTURING METHOD THEREFOR, WRITING METHOD THEREFOR, READING METHOD THEREFOR, AND RECORDING MEDIUM AND SEMICONDUCTOR MEMORY DEVICE

摘要

PROBLEM TO BE SOLVED: To easily and surely adjust the amount of charge capture and prevent defects such as corruption of information and to store desired multi-valued information.SOLUTION: A semiconductor memory device includes: a channel region C between a source region 3 and a drain region 4; a gate electrode 6; and a charge capture film 5 which is disposed between the channel region C and the gate electrode 6. The charge capture film 5 includes a gate oxide film 11, a silicon nitride film 12, a silicon oxide film 13, a silicon nitride film 14, a silicon oxide film 15, a silicon nitride film 16, and a silicon oxide film 17 laminated in this order. Four-valued information ("00", "01", "10", "11") is memorized by accumulating charges in traps formed between nitride films 12, 14, 16 and their oxide underlayers 11, 13, 15, 17, respectively.