| 摘要 |
PURPOSE:To obtain a memory cell which has long lifetime and good reliability by passing carriers through individual tunnel insulating films due to tunnel phenomenon at writing and erasing times. CONSTITUTION:A conductor layer 5 which forms a floating gate is buried at the part which reaches from above a drain impurity diffused layer 2 to above a source impurity diffused layer 3 is buried. A conductor layer 8 is buried at the part in the vicinity of the layer 3 side of the layer 5 in an insulating film 4 in which a conductor layer 7 forming a control gate is buried at the part above the layer 5. The films 4 between the layer 2 and the end of the drain impurity diffused layer side of the layer 5 as well as between the layer 8 and the source impurity layer side end of the layer 5 are respectively formed as the first and second tunnel insulating films 6, 9 which are alternately used at the writing and erasing times. |
