| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve a nonvolatile semiconductor memory device in data holding properties and withstand voltage. SOLUTION: A charge storage layer 20 provided to a nonvolatile semiconductor memory device is constituted of a lower oxide film 23, a nitride film 24, and an upper oxide film 26. At this point, the nitride film 24 is formed so as to be isolated from another memory cell transistor. With this setup, charges trapped near an interface between the lower oxide film 23 and the nitride 24 can be restrained from moving and spreading, and a memory cell transistor is restrained from varying in threshold and improved in data holding properties.</p> |
