Non-volatile semiconductor information storage device

A non-volatile semiconductor information storage device including:

• a semiconductor substrate having a first conductivity type;
• and
• a plurality of memory transistors on said semiconductor substrate, each of said memory transistors comprising:
• a source region and a drain region in said semiconductor substrate and having a second conductivity type, opposite the first conductivity type, of said semiconductor substrate;
• a gate electrode on said semiconductor substrate between said source region and said drain region and having, laminated in a stack successively on said semiconductor substrate, a first gate oxide film, a first floating gate electrode, a second gate oxide film, a second floating gate electrode, a gate insulating film, a control gate electrode, and a third gate oxide film so that electrons are injected into said first floating gate electrode from said semiconductor substrate through said first gate oxide film and electrons are injected into said second floating gate electrode from said first floating gate electrode through said second gate oxide film;
• and
• an erase gate electrode located beside said gate electrode.