Method for deleting data from nand type nonvolatile memory

A nonvolatile semiconductor memory device comprising:

• a single crystalline semiconductor layer on an insulating surface, the semiconductor layer including a channel formation region between a pair of impurity regions formed apart from each other;
• a first insulating layer over the channel formation region;
• a first nitride film on the first insulating layer;
• a charge accumulating layer over the channel formation region with the first insulating layer and the first nitride film interposed therebetween;
• a second nitride film on the charge accumulating layer;
• a second insulating layer over the charge accumulating layer;
• and
• a control gate over the charge accumulating layer with the second nitride film and the second insulating layer interposed therebetween.

A nonvolatile semiconductor memory device comprising:

• a single crystalline semiconductor layer on an insulating surface, the semiconductor layer including a channel formation region between a pair of impurity regions formed apart from each other;
• a first insulating layer over the channel formation region;
• a first nitride film on the first insulating layer;
• a charge accumulating layer over the channel formation region with the first insulating layer and the first nitride film interposed therebetween;
• a second nitride film on the charge accumulating layer;
• a second insulating layer over the charge accumulating layer;
• and
• a control gate over the charge accumulating layer with the second nitride film and the second insulating layer interposed therebetween,
• wherein the second insulating layer comprises a material selected from the group consisting of aluminum oxide, hafnium oxide and tantalum oxide.