| 摘要 |
<p>PROBLEM TO BE SOLVED: To accurately detect a point where an operational degradation occurs and whether it is related to a programming, an erasing, or a reading operation by a method wherein an active region is demarcated so as to be isolated, and a source region and a drain region are separated from each other by a cell. SOLUTION: A field oxide film 2 is formed on a semiconductor substrate through an element isolation process. In result, at least three isolated active regions 100 are defined. A cell is formed in each of the active regions on its right and left part respectively sandwiching a drain region 9 between them, a first common floating gate 4A is formed in the active regions 100 so as to hold the left cells in common, and a second common floating gate 4B is formed so as to hold the right cells in common. Furthermore, a select gate 12 is formed in the active regions 100 so as to pass above two stacked transistor patterns, two source region 8 and two drain regions 9.</p> |
