Nonvolatile semiconductor storage device and manufacturing method thereof
First Claim
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1. A method for manufacturing a nonvolatile semiconductor storage device, comprising:
- forming a first semiconductor film and a second semiconductor film, over a substrate having an insulating surface;
forming a first insulating film on a surface of the first semiconductor film and a surface of the second semiconductor film, comprising;
an oxide film formed by performing first high-density plasma treatment under an oxygen atmosphere; and
a film including oxygen and nitrogen formed on the oxide film, formed by performing second high-density plasma treatment under a nitrogen atmosphere;
forming a charge accumulating layer comprising a material with a smaller energy gap than the first semiconductor film and the second semiconductor film over the first insulating film;
forming a second insulating film over the charge accumulating layer;
removing selectively the first insulating film, the charge accumulating layer, and the second insulating film which are formed over the second semiconductor film so as to expose the surface of the second semiconductor film;
oxidizing a surface of the second insulating film by performing third high-density plasma treatment under an oxygen atmosphere;
forming a conductive film over the oxidized surface of the second insulating film;
removing selectively the first insulating film, the charge accumulating layer, the second insulating film, and the conductive film, thereby leaving parts of the first insulating film, the charge accumulating layer, the second insulating film, and the conductive film so as to overlap with at least a part of the first semiconductor film; and
forming an impurity region in the first semiconductor film and the second semiconductor film, by introducing an impurity element, with the parts of the conductive film, formed over the first semiconductor film and the second semiconductor film, used as a mask, respectively.
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Abstract
An object of the present invention is to provide a nonvolatile semiconductor storage device with a superior charge holding characteristic in which highly-efficient writing is possible at low voltage, and to provide a manufacturing method thereof.
The nonvolatile semiconductor storage device includes a semiconductor film having a pair of impurity regions formed apart from each other and a channel formation region provided between the impurity regions; and a first insulating film, a charge accumulating layer, a second insulating film, and a conductive film functioning as a gate electrode layer which are provided over the channel formation region. In the nonvolatile semiconductor storage device, a second barrier formed by the first insulating film against a charge of the charge accumulating layer is higher in energy than a first barrier formed by the first insulating film against a charge of the semiconductor film.
75 Citations
16 Claims
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1. A method for manufacturing a nonvolatile semiconductor storage device, comprising:
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forming a first semiconductor film and a second semiconductor film, over a substrate having an insulating surface; forming a first insulating film on a surface of the first semiconductor film and a surface of the second semiconductor film, comprising; an oxide film formed by performing first high-density plasma treatment under an oxygen atmosphere; and a film including oxygen and nitrogen formed on the oxide film, formed by performing second high-density plasma treatment under a nitrogen atmosphere; forming a charge accumulating layer comprising a material with a smaller energy gap than the first semiconductor film and the second semiconductor film over the first insulating film; forming a second insulating film over the charge accumulating layer; removing selectively the first insulating film, the charge accumulating layer, and the second insulating film which are formed over the second semiconductor film so as to expose the surface of the second semiconductor film; oxidizing a surface of the second insulating film by performing third high-density plasma treatment under an oxygen atmosphere; forming a conductive film over the oxidized surface of the second insulating film; removing selectively the first insulating film, the charge accumulating layer, the second insulating film, and the conductive film, thereby leaving parts of the first insulating film, the charge accumulating layer, the second insulating film, and the conductive film so as to overlap with at least a part of the first semiconductor film; and forming an impurity region in the first semiconductor film and the second semiconductor film, by introducing an impurity element, with the parts of the conductive film, formed over the first semiconductor film and the second semiconductor film, used as a mask, respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for manufacturing a nonvolatile semiconductor storage device, comprising:
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forming a first semiconductor film and a second semiconductor film, over a substrate having an insulating surface; forming a first insulating film on a surface of the first semiconductor film and a surface of the second semiconductor film, by performing first high-density plasma treatment under an oxygen atmosphere and then performing second high-density plasma treatment under a nitrogen atmosphere; forming a charge accumulating layer comprising a material with a smaller energy gap than the first semiconductor film and the second semiconductor film over the first insulating film; forming a second insulating film over the charge accumulating layer; removing selectively the first insulating film, the charge accumulating layer, and the second insulating film which are formed over the second semiconductor film so as to expose the surface of the second semiconductor film; oxidizing a surface of the second insulating film formed over the first semiconductor film and simultaneously forming a gate insulating film on the surface of the second semiconductor film, by performing third high-density plasma treatment under an oxygen atmosphere; forming a conductive film over the oxidized surface of the second insulating film and over the gate insulating film; removing selectively the first insulating film, the charge accumulating layer, the second insulating film, the gate insulating film, and the conductive film, thereby leaving parts of the first insulating film, the charge accumulating layer, the second insulating film, and the conductive film so as to overlap with at least a part of the first semiconductor film and leaving parts of the gate insulating film and the conductive film so as to overlap with at least a part of the second semiconductor film; and forming an impurity region in the first semiconductor film and the second semiconductor film by introducing an impurity element with the parts of the conductive film, formed over the first semiconductor film and the second semiconductor film, used as a mask, respectively. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Current AssigneeSemiconductor Energy Laboratory Co., Ltd.
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Original AssigneeSemiconductor Energy Laboratory Co., Ltd.
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InventorsYamazaki, Shunpei
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Primary Examiner(s)Lee, Hsien Ming
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Application NumberUS12/718,011Publication NumberTime in Patent Office1,026 DaysField of Search438/279, 438/283, 438/287, 438/305, 438/306, 438/308US Class Current438/279CPC Class CodesH01L 27/1214 comprising a plurality of T...H01L 27/1237 with a different compositio...H01L 29/40114 the electrodes comprising a...H01L 29/42324 Gate electrodes for transis...H10B 41/30 characterised by the memory...H10B 41/40 characterised by the periph...H10B 41/44 with a control gate layer a...H10B 41/46 with an inter-gate dielectr...H10B 41/49 comprising different types ...H10B 69/00 Erasable-and-programmable R...
