| 摘要 |
A nonvolatile semiconductor memory device comprises a memory cell. The memory cell includes a first gate insulating film formed on a semiconductor substrate, a floating gate formed on the first gate insulating film, a second gate insulating film formed on the floating gate, and a control gate formed on the second gate insulating film. The floating gate includes a first semiconductor film which contacts the first gate insulating film, and a metal film stacked on the semiconductor film. An effective tunneling thickness between the semiconductor substrate and the floating gate in a read operation is thicker than an effective tunneling thickness between the semiconductor substrate and the floating in a write operation.
|
