SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF
First Claim
1. A semiconductor device comprising:
- a first transistor over a substrate; and
a second transistor over the substrate, the first transistor and the second transistor each comprising;
a first electrode layer;
a first insulating film over the first electrode layer;
an oxide semiconductor layer over the first insulating film;
a second electrode layer on the oxide semiconductor layer, the second electrode layer having a first end portion overlapping with the first electrode layer;
a third electrode layer on the oxide semiconductor layer, the third electrode layer having a second end portion overlapping with the first electrode layer;
a second insulating film including an oxide insulating film, the oxide insulating film in contact with the second electrode layer, the third electrode layer, and the oxide semiconductor layer; and
a fourth electrode layer over the first electrode layer with at least the oxide semiconductor layer and the second insulating film interposed therebetween,wherein a first region including a surface portion of the oxide semiconductor layer comprises a crystalline region, andwherein an energy gap of an oxide semiconductor included in the oxide semiconductor layer is greater than or equal to 2 eV.
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Accused Products
Abstract
An oxide semiconductor layer which is intrinsic or substantially intrinsic and includes a crystalline region in a surface portion of the oxide semiconductor layer is used for the transistors. An intrinsic or substantially intrinsic semiconductor from which an impurity which is to be an electron donor (donor) is removed from an oxide semiconductor and which has a larger energy gap than a silicon semiconductor is used. Electrical characteristics of the transistors can be controlled by controlling the potential of a pair of conductive films which are provided on opposite sides from each other with respect to the oxide semiconductor layer, each with an insulating film arranged therebetween, so that the position of a channel formed in the oxide semiconductor layer is determined.
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Citations
14 Claims
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1. A semiconductor device comprising:
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a first transistor over a substrate; and a second transistor over the substrate, the first transistor and the second transistor each comprising; a first electrode layer; a first insulating film over the first electrode layer; an oxide semiconductor layer over the first insulating film; a second electrode layer on the oxide semiconductor layer, the second electrode layer having a first end portion overlapping with the first electrode layer; a third electrode layer on the oxide semiconductor layer, the third electrode layer having a second end portion overlapping with the first electrode layer; a second insulating film including an oxide insulating film, the oxide insulating film in contact with the second electrode layer, the third electrode layer, and the oxide semiconductor layer; and a fourth electrode layer over the first electrode layer with at least the oxide semiconductor layer and the second insulating film interposed therebetween, wherein a first region including a surface portion of the oxide semiconductor layer comprises a crystalline region, and wherein an energy gap of an oxide semiconductor included in the oxide semiconductor layer is greater than or equal to 2 eV. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for manufacturing a first transistor and a second transistor of a semiconductor device comprising the steps of:
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forming a first electrode layer; forming a first insulating film over the first electrode layer; forming an oxide semiconductor layer over the first insulating film; performing dehydration or dehydrogenation on the oxide semiconductor layer, so that a crystalline region is formed in a first region including a surface portion of the oxide semiconductor layer; forming a second electrode layer and a third electrode layer on the oxide semiconductor layer, the second electrode layer having a first end portion overlapping with the first electrode layer, and the third electrode layer having a second end portion overlapping with the first electrode layer; forming a second insulating film including an oxide insulating film, the oxide insulating film in contact with the second electrode layer, the third electrode layer, and the oxide semiconductor layer; and forming a fourth electrode layer over the first electrode layer with at least the oxide semiconductor layer and the second insulating film interposed therebetween, wherein an energy gap of an oxide semiconductor included in the oxide semiconductor layer is greater than or equal to 2 eV, and wherein the first transistor and the second transistor are formed over a substrate. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification