Nonvolatile semiconductor storage device and manufacturing method thereof
First Claim
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1. A nonvolatile semiconductor storage device comprising:
- a substrate having an insulating surface;
a semiconductor film over the substrate, having a pair of impurity regions formed apart from each other and a channel formation region provided between the pair of impurity regions;
a first insulating film provided over the channel formation region;
a charge accumulating layer provided over the first insulating film;
a second insulating film provided over the charge accumulating layer; and
a gate electrode layer provided over the second insulating film, wherein a first energy barrier is formed by the first insulating film against a charge of the semiconductor film, wherein a second energy barrier is formed by the first insulating film against a charge of the charge accumulating layer, and wherein the second energy barrier is higher than the first energy barrier.
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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
64 Claims
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1. A nonvolatile semiconductor storage device comprising:
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a substrate having an insulating surface;
a semiconductor film over the substrate, having a pair of impurity regions formed apart from each other and a channel formation region provided between the pair of impurity regions;
a first insulating film provided over the channel formation region;
a charge accumulating layer provided over the first insulating film;
a second insulating film provided over the charge accumulating layer; and
a gate electrode layer provided over the second insulating film, wherein a first energy barrier is formed by the first insulating film against a charge of the semiconductor film, wherein a second energy barrier is formed by the first insulating film against a charge of the charge accumulating layer, and wherein the second energy barrier is higher than the first energy barrier. - View Dependent Claims (7)
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2. A nonvolatile semiconductor storage device comprising:
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a substrate having an insulating surface;
a semiconductor film over the substrate, having a pair of impurity regions formed apart from each other and a channel formation region provided between the pair of impurity regions;
a first insulating film provided over the channel formation region;
a charge accumulating layer provided over the first insulating film;
a second insulating film provided over the charge accumulating layer; and
a gate electrode layer provided over the second insulating film, wherein the charge accumulating layer comprises a material with a smaller energy gap than the semiconductor film, - View Dependent Claims (8)
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3. A nonvolatile semiconductor storage device comprising:
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a substrate having an insulating surface;
a first semiconductor film over the substrate, having a pair of first impurity regions formed apart from each other and a first channel formation region provided between the pair of first impurity regions;
a first insulating film provided over the first channel formation region;
a charge accumulating layer provided over the first insulating film;
a second insulating film provided over the charge accumulating layer;
a first gate electrode layer provided over the second insulating film;
a second semiconductor film over the substrate, having a pair of second impurity regions formed apart from each other and a second channel formation region provided between the pair of second impurity regions;
a third insulating film provided over the second channel forming region; and
a second gate electrode layer provided over the third insulating film, wherein a first energy barrier is formed by the first insulating film against a charge of the first semiconductor film, wherein a second energy barrier is formed by the first insulating film against a charge of the charge accumulating layer, and wherein the second energy barrier is higher than the first energy barrier. - View Dependent Claims (5, 9, 11)
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4. A nonvolatile semiconductor storage device comprising:
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a substrate having an insulating surface;
a first semiconductor film over the substrate, having a pair of first impurity regions formed apart from each other and a first channel formation region provided between the pair of first impurity regions;
a first insulating film provided over the first channel formation region;
a charge accumulating layer provided over the first insulating film;
a second insulating film provided over the charge accumulating layer;
a first gate electrode layer provided over the second insulating film;
a second semiconductor film over the substrate, having a pair of second impurity regions formed apart from each other and a second channel formation region provided between the pair of second impurity regions;
a third insulating film provided over the second channel forming region; and
a second gate electrode layer provided over the third insulating film, wherein the charge accumulating layer comprises a material with a smaller energy gap than the first semiconductor film. - View Dependent Claims (6, 10, 12)
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13. A method for manufacturing a nonvolatile semiconductor storage device, comprising:
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forming a semiconductor film over a substrate having an insulating surface;
forming a first insulating film on a surface of the semiconductor film, comprising at least one of oxygen and nitrogen, by performing high-density plasma treatment;
forming a charge accumulating layer comprising a material with a smaller energy gap than the semiconductor film, over the first insulating film;
forming a second insulating film over the charge accumulating layer;
forming a conductive film over the second insulating film;
removing selectively the first insulating film, the charge accumulating layer, the second insulating film and the conductive film, thereby leaving 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 semiconductor film; and
forming an impurity region in the semiconductor film, by introducing an impurity element, with a left part of the conductive film used as a mask. - View Dependent Claims (20, 25, 30, 35, 45, 50)
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14. A method for manufacturing a nonvolatile semiconductor storage device, comprising:
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forming a semiconductor film over a substrate having an insulating surface;
forming a first insulating film on a surface of the 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 semiconductor film over the first insulating film;
forming a second insulating film over the charge accumulating layer;
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 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 semiconductor film; and
forming an impurity region in the semiconductor film, by introducing an impurity element, with a left part of the conductive film used as a mask. - View Dependent Claims (16, 21, 26, 31, 36, 46, 51)
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15. 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 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 a 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 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 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 a left part of the conductive film used as a mask. - View Dependent Claims (17, 22, 27, 32, 37, 47, 52)
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18. A method for manufacturing a nonvolatile semiconductor storage device, comprising:
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forming a semiconductor film over a substrate having an insulating surface;
forming a first insulating film on a surface of the semiconductor film, comprising at least one of oxygen and nitrogen, by performing high-density plasma treatment;
forming a charge accumulating layer comprising a material with a smaller energy gap than the 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, the second insulating film, and the conductive film so as to expose at least a part of the semiconductor film;
oxidizing a surface of a left part of the second insulating film and an exposed surface of the semiconductor film by performing second high-density plasma treatment under an oxygen atmosphere;
forming a conductive film over the oxidized surface of the left part of the second insulating film and over the surface of the semiconductor film that is oxidized by the second high-density plasma treatment;
removing selectively the conductive film so as to overlap the left part of the second insulating film at least partly; and
forming an impurity region in the semiconductor film by introducing an impurity element with a left part of the conductive film used as a mask. - View Dependent Claims (23, 28, 33, 38, 48, 53)
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19. A method for manufacturing a nonvolatile semiconductor storage device, comprising;
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forming a semiconductor film over a substrate having an insulating surface;
forming a first insulating film on a surface of the semiconductor film, comprising at least one of oxygen and nitrogen, by performing high-density plasma treatment;
forming a charge accumulating layer comprising a material with a smaller energy gap than the 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, the second insulating film, and the conductive film so as to expose at least a part of the semiconductor film;
oxidizing a surface of a left part of the second insulating film and an exposed surface of the semiconductor film by performing second high-density plasma treatment under an oxygen atmosphere;
forming a conductive film over the second insulating film over the oxidized surface of the left part of the second insulating film and over the surface of the semiconductor film that is oxidized by the second high-density plasma treatment;
removing selectively the conductive film so that a part of the surface and a side face of the second insulating film of which surface has been oxidized are exposed; and
forming a first impurity region in a region of the semiconductor film that does not overlap with the first insulating film, the charge accumulating layer, the second insulating film and the conductive film, and forming a second impurity region with lower concentration than in the first impurity region, in a region of the semiconductor film that does not overlap with the first insulating film, the charge accumulating layer, the second insulating film, and the conductive film by adding an impurity element in the semiconductor film with the conductive film used as a mask. - View Dependent Claims (24, 29, 34, 39, 49, 54)
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40-44. -44. (canceled)
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55-58. -58. (canceled)
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59. A nonvolatile semiconductor storage device comprising:
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a substrate having an insulating surface;
a semiconductor film formed over the substrate, having a pair of impurity regions formed apart from each other and a channel formation region provided between the pair of impurity regions;
a first insulating film provided over the channel formation region;
a charge accumulating layer comprises germanium, provided over the first insulating film;
a second insulating film provided over the charge accumulating layer; and
a gate electrode layer provided over the second insulating film. - View Dependent Claims (60, 61, 62, 63)
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64. (canceled)
Specification
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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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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current257/324
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CPC 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...
