| 摘要 |
PROBLEM TO BE SOLVED: To reduce false read and to improve reliability of flash memory by reducing threshold shift provided by potential change of an adjacent cell in a word line direction. SOLUTION: A memory cell of a flash memory is formed in a p-type well 10 of a semiconductor substrate 1; and has a gate insulating film 4, a floating gate 5, a high dielectric film 6, and a control gate 8 (word line WL). The floating gate 5 and the control gate 8 (word line WL) are separated by the high dielectric film 6. A plurality of memory cells arranged in lines are separated by an isolation groove 3 extended in columns. A silicon oxide film 24 is buried inside the isolation groove 3. A cavity 15 is provided to an inside of the silicon oxide film 24. A lower end of the cavity 15 extends to an area near a bottom of the isolation groove 3, and an upper end thereof extends further above an upper surface of the high dielectric film 6 covering the floating gate 5. COPYRIGHT: (C)2008,JPO&INPIT
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