Nonvolatile semiconductor memory device suppressing fluctuation in threshold voltage
AssigneeKabushiki Kaisha Toshiba
InventorToshitake Yaegashi
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Abstract
First and second memory cell transistors are isolated by an element isolation insulating film. A barrier insulating film covers the element isolation insulating film. The first memory cell transistor includes a first tunnel insulating film, a first charge storage layer made of an insulating film, a first block insulating film, and a first gate electrode. The second memory cell transistor includes a second tunnel insulating film, a second charge storage layer made of an insulating film, a second block insulating film, and a second gate electrode. The barrier insulating film is in contact with the first and second charge storage layers, and has a film thickness smaller than that of the first and second charge storage layers.
Claims20
A nonvolatile semiconductor memory device comprising:
- a semiconductor substrate;
- a first element isolation insulating film formed in the semiconductor substrate;
- a first memory cell transistor and a second memory cell transistor isolated by the first element isolation insulating film;
- and
- a first barrier insulating film covering the first element isolation insulating film,
- the first memory cell transistor including
- a first tunnel insulating film formed on the semiconductor substrate,
- a first charge storage layer formed on the first tunnel insulating film and made of an insulating film,
- a first block insulating film formed on the first charge storage layer, and
- a first gate electrode formed on the first block insulating film,
- the second memory cell transistor including
- a second tunnel insulating film formed on the semiconductor substrate,
- a second charge storage layer formed on the second tunnel insulating film and made of an insulating film,
- a second block insulating film formed on the second charge storage layer, and
- a second gate electrode formed on the second block insulating film, and
- the first barrier insulating film being in contact with the first charge storage layer and the second charge storage layer, and having a film thickness smaller than that of the first charge storage layer and the second charge storage layer.
A nonvolatile semiconductor memory device comprising:
- a semiconductor substrate;
- a first element isolation insulating film formed in the semiconductor substrate;
- a first memory cell transistor and a second memory cell transistor isolated by the first element isolation insulating film;
- and
- a first barrier insulating film covering the first element isolation insulating film,
- the first memory cell transistor including
- a first tunnel insulating film formed on the semiconductor substrate,
- a first charge storage layer formed on the first tunnel insulating film and made of an insulating film,
- a first block insulating film formed on the first charge storage layer, and
- a first gate electrode formed on the first block insulating film,
- the second memory cell transistor including
- a second tunnel insulating film formed on the semiconductor substrate,
- a second charge storage layer formed on the second tunnel insulating film and made of an insulating film,
- a second block insulating film formed on the second charge storage layer, and
- a second gate electrode formed on the second block insulating film, and
- the first barrier insulating film being in contact with the first charge storage layer and the second charge storage layer, and made of an insulating film different from the first charge storage layer and the second charge storage layer.
Dependencies are inferred from the claim text.