| 摘要 |
<p>Provided is an electrically erasable and programmable nonvolatile semiconductor memory device having a small hole in a second conductivity-type drain region, a tunnel insulating film formed on the surface of the hole, and a protrusion extended from the floating gate electrode and arranged to fill the hole. Further a tunneling restriction region which is an electrically floating first conductivity type region arranged in a vicinity of the surface of the drain region around the hole to define the size of the tunnel region through which the tunnel current flows.</p> |
