Oxide semiconductor, thin film transistor, and display device
First Claim
1. A thin film transistor comprising:
- an oxide semiconductor layer;
a first silicon oxide layer and a second silicon oxide layer sandwiching the oxide semiconductor layer, each of the first silicon oxide layer and the second silicon oxide layer being in direct contact with the oxide semiconductor layer; and
a first nitride insulating layer and a second nitride insulating layer sandwiching a stack formed of the oxide semiconductor layer, the first silicon oxide layer and the second silicon oxide layer,wherein the oxide semiconductor layer comprises O, In, Ga, and Zn, and wherein a concentration of Zn is comprised between 5 atomic % and 10 atomic %, andwherein concentrations of In and Ga are each comprised between 15 atomic % and 20 atomic %.
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Accused Products
Abstract
An object is to control composition and a defect of an oxide semiconductor, another object is to increase a field effect mobility of a thin film transistor and to obtain a sufficient on-off ratio with a reduced off current. A solution is to employ an oxide semiconductor whose composition is represented by InMO3(ZnO)m, where M is one or a plurality of elements selected from Ga, Fe, Ni, Mn, Co, and Al, and m is preferably a non-integer number of greater than 0 and less than 1. The concentration of Zn is lower than the concentrations of In and M. The oxide semiconductor has an amorphous structure. Oxide and nitride layers can be provided to prevent pollution and degradation of the oxide semiconductor.
143 Citations
39 Claims
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1. A thin film transistor comprising:
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an oxide semiconductor layer; a first silicon oxide layer and a second silicon oxide layer sandwiching the oxide semiconductor layer, each of the first silicon oxide layer and the second silicon oxide layer being in direct contact with the oxide semiconductor layer; and a first nitride insulating layer and a second nitride insulating layer sandwiching a stack formed of the oxide semiconductor layer, the first silicon oxide layer and the second silicon oxide layer, wherein the oxide semiconductor layer comprises O, In, Ga, and Zn, and wherein a concentration of Zn is comprised between 5 atomic % and 10 atomic %, and wherein concentrations of In and Ga are each comprised between 15 atomic % and 20 atomic %. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A thin film transistor comprising:
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an oxide semiconductor layer; a first silicon oxide layer and a second silicon oxide layer sandwiching the oxide semiconductor layer, each of the first silicon oxide layer and the second silicon oxide layer being in direct contact with the oxide semiconductor layer; and a first nitride insulating layer and a second nitride insulating layer sandwiching a stack formed of the oxide semiconductor layer, the first silicon oxide layer and the second silicon oxide layer, wherein the oxide semiconductor layer comprises O, In, Ga, and Zn. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A thin film transistor comprising:
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a gate electrode layer; an oxide semiconductor layer; a first silicon oxide layer and a second silicon oxide layer sandwiching the oxide semiconductor layer, each of the first silicon oxide layer and the second silicon oxide layer being in contact with the oxide semiconductor layer; and a first nitride insulating layer and a second nitride insulating layer sandwiching a stack comprising the oxide semiconductor layer, the first silicon oxide layer, and the second silicon oxide layer, wherein the first nitride insulating layer and the first silicon oxide layer are interposed between the gate electrode layer and the oxide semiconductor layer, wherein the second nitride insulating layer is in contact with the second silicon oxide layer, and wherein the oxide semiconductor layer comprises O, In, Ga, and Zn. - View Dependent Claims (16, 17, 18, 19)
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20. A thin film transistor comprising:
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a gate electrode layer; an oxide semiconductor layer; a first silicon oxide layer and a second silicon oxide layer sandwiching the oxide semiconductor layer, each of the first silicon oxide layer and the second silicon oxide layer being in contact with the oxide semiconductor layer; and a first nitride insulating layer and a second nitride insulating layer sandwiching a stack comprising the oxide semiconductor layer, the first silicon oxide layer, and the second silicon oxide layer, wherein the first nitride insulating layer and the first silicon oxide layer are interposed between the gate electrode layer and the oxide semiconductor layer, wherein, when seen in cross-section along the channel formation region, the gate electrode layer has a larger width than the oxide semiconductor layer, and wherein the oxide semiconductor layer comprises O, In, Ga, and Zn. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. A thin film transistor comprising:
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an oxide semiconductor layer; a first oxide insulating layer and a second oxide insulating layer sandwiching the oxide semiconductor layer, each of the first oxide insulating layer and the second oxide insulating layer being in direct contact with the oxide semiconductor layer; and a first nitride insulating layer and a second nitride insulating layer sandwiching a stack formed of the oxide semiconductor layer, the first oxide insulating layer and the second oxide insulating layer. - View Dependent Claims (29, 30, 31, 32)
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33. A thin film transistor comprising:
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an oxide semiconductor layer; a first insulating layer and a second insulating layer each comprising oxygen and silicon sandwiching the oxide semiconductor layer, each of the first insulating layer and the second insulating layer being in direct contact with the oxide semiconductor layer; and a third insulating layer and a fourth insulating layer each comprising nitrogen and sandwiching a stack formed of the oxide semiconductor layer, the first insulating layer and the second insulating layer. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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Specification