Semiconductor device and method for manufacturing the same
First Claim
1. A semiconductor device comprising:
- a gate electrode over a substrate;
a gate insulating film over the gate electrode;
a first electrode and a second electrode over the gate insulating film;
a first wiring over the first electrode;
a second wiring over the second electrode;
an oxide semiconductor layer over the first wiring and the second wiring, the oxide semiconductor layer being in contact with a side face and a top face of each of the first electrode and the second electrode and a side face and a top face of each of the first wiring and the second wiring; and
a protective insulating layer over the oxide semiconductor layer,wherein the first electrode is extended so as to have an end portion positioned more inwardly than an end portion of the first wiring and overlap with the gate electrode, and the second electrode is extended so as to have an end portion positioned more inwardly than an end portion of the second wiring and overlap with the gate electrode,wherein the first wiring and the second wiring do not overlap with the gate electrode,wherein electrical conductivity of each of the first electrode and the second electrode is equal to or higher than electrical conductivity of the oxide semiconductor layer,wherein electrical conductivity of the first electrode is equal to or lower than electrical conductivity of the first wiring,wherein electrical conductivity of the second electrode is equal to or lower than electrical conductivity of the second wiring, andwherein the protective insulating layer has direct contact with the gate insulating film, the first wiring, the second wiring, and the oxide semiconductor layer without having direct contact with any portion of the first electrode and the second electrode.
1 Assignment
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Accused Products
Abstract
The drain voltage of a transistor is determined depending on the driving voltage of an element connected to the transistor. With downsizing of a transistor, intensity of the electric field concentrated in the drain region is increased, and hot carriers are easily generated. An object is to provide a transistor in which the electric field hardly concentrates in the drain region. Another object is to provide a display device including such a transistor. End portions of first and second wiring layers having high electrical conductivity do not overlap with a gate electrode layer, whereby concentration of an electric field in the vicinity of a first electrode layer and a second electrode layer is reduced; thus, generation of hot carriers is suppressed. In addition, one of the first and second electrode layers having higher resistivity than the first and second wiring layers is used as a drain electrode layer.
132 Citations
17 Claims
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1. A semiconductor device comprising:
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a gate electrode over a substrate; a gate insulating film over the gate electrode; a first electrode and a second electrode over the gate insulating film; a first wiring over the first electrode; a second wiring over the second electrode; an oxide semiconductor layer over the first wiring and the second wiring, the oxide semiconductor layer being in contact with a side face and a top face of each of the first electrode and the second electrode and a side face and a top face of each of the first wiring and the second wiring; and a protective insulating layer over the oxide semiconductor layer, wherein the first electrode is extended so as to have an end portion positioned more inwardly than an end portion of the first wiring and overlap with the gate electrode, and the second electrode is extended so as to have an end portion positioned more inwardly than an end portion of the second wiring and overlap with the gate electrode, wherein the first wiring and the second wiring do not overlap with the gate electrode, wherein electrical conductivity of each of the first electrode and the second electrode is equal to or higher than electrical conductivity of the oxide semiconductor layer, wherein electrical conductivity of the first electrode is equal to or lower than electrical conductivity of the first wiring, wherein electrical conductivity of the second electrode is equal to or lower than electrical conductivity of the second wiring, and wherein the protective insulating layer has direct contact with the gate insulating film, the first wiring, the second wiring, and the oxide semiconductor layer without having direct contact with any portion of the first electrode and the second electrode. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A semiconductor device comprising:
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a gate electrode over a substrate; a gate insulating film overlapping with the gate electrode; a first electrode and a second electrode overlapping with the gate insulating film; a first wiring overlapping with the first electrode; a second wiring overlapping with the second electrode; an oxide semiconductor layer over the first wiring and the second wiring, the oxide semiconductor layer being in contact with a side face and a top face of each of the first electrode and the second electrode and a side face and a top face of each of the first wiring and the second wiring; and a protective insulating layer over the oxide semiconductor layer, wherein the first electrode is extended so as to have an end portion positioned more inwardly than an end portion of the first wiring and overlap with the gate electrode, and the second electrode is extended so as to have an end portion positioned more inwardly than an end portion of the second wiring and overlap with the gate electrode, wherein the first wiring and the second wiring do not overlap with the gate electrode, wherein electrical conductivity of each of the first electrode and the second electrode is equal to or higher than electrical conductivity of the oxide semiconductor layer, wherein electrical conductivity of the first electrode is equal to or lower than electrical conductivity of the first wiring, wherein electrical conductivity of the second electrode is equal to or lower than electrical conductivity of the second wiring, and wherein the protective insulating layer has direct contact with the gate insulating film, the first wiring, the second wiring, and the oxide semiconductor layer without having direct contact with any portion of the first electrode and the second electrode. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A semiconductor device comprising:
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a gate electrode over a substrate; a gate insulating film overlapping with the gate electrode; a first electrode and a second electrode overlapping with the gate insulating film; a first wiring overlapping with the first electrode; a second wiring overlapping with the second electrode; an oxide semiconductor layer over the first wiring and the second wiring, the oxide semiconductor layer being in contact with a side face and a top face of each of the first electrode and the second electrode and a side face and a top face of each of the first wiring and the second wiring; and a protective insulating layer over the oxide semiconductor layer, wherein the first electrode is extended so as to have an end portion positioned more inwardly than an end portion of the first wiring and overlap with the gate electrode, and the second electrode is extended so as to have an end portion positioned more inwardly than an end portion of the second wiring and overlap with the gate electrode, wherein the first wiring and the second wiring do not overlap with the gate electrode, and wherein the protective insulating layer has direct contact with the gate insulating film, the first wiring, the second wiring, and the oxide semiconductor layer without having direct contact with any portion of the first electrode and the second electrode. - View Dependent Claims (14, 15, 16, 17)
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Specification