| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor storage device having a double well which is advantageous to microfabrication, and wells separated from the double well. SOLUTION: The nonvolatile semiconductor storage device includes a first conductive type first well 10 formed in a first conductive type semiconductor substrate 1, a plurality of memory-cell transistors Q5-1, Q5-2 formed in the first well 10, a second conductive type second well, and a second conductive type third well region 5 formed in the semiconductor substrate 1. The second well has a first portion 7 surrounding a side face region of the first well 10, and a second portion 9 surrounding a lower region of the first well 10, and electrically separates the first well 10 from the semiconductor substrate 1. COPYRIGHT: (C)2009,JPO&INPIT
|
