NONVOLATILE SEMICONDUCTOR MEMORY ELEMENT, NONVOLATILE SEMICONDUCTOR DEVICE, AND METHOD FOR OPERATING NONVOLATILE SEMICONDUCTOR ELEMENT

摘要

PROBLEM TO BE SOLVED: To effectively suppress a change of a threshold value for a nonvolatile semiconductor memory element during holding data by effectively suppressing charge emission from the upper insulating layer of the nonvolatile semiconductor memory element when holding the data.

SOLUTION: The nonvolatile semiconductor memory element includes: a semiconductor substrate 1; a source region 2 and a domain region 3 provided in the surface of the semiconductor substrate 1; a tunnel insulating film 4 provided on the semiconductor substrate; a conductive charge accumulating layer 5 provided on the tunnel insulating film 4; the upper insulating layer 6 provided on the conductive charge accumulating layer 5; and a control gate 7 provided on the upper insulating layer 6. The upper insulating layer 6 is a laminated structure consisting of a transmission insulating layer 6a, a charge trapping layer 6b and a block layer 6c. The trap level density of the charge trapping layer 6b is greater than the trap level density of each of the transmission insulating layer 6a and the block layer 6c, and a leak current in the transmission insulating layer 6a is higher than a leak current in the block layer 6c.

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