Oxide semiconductor, thin film transistor, and display device
First Claim
1. A semiconductor device comprising:
- a first conductive layer;
a second conductive layer;
a first insulating layer over the first conductive layer and the second conductive layer;
an oxide semiconductor layer over the first insulating layer;
a third conductive layer electrically connected to the oxide semiconductor layer;
a fourth conductive layer electrically connected to the oxide semiconductor layer; and
a fifth conductive layer over the first insulating layer,wherein the first conductive layer includes a region functioning as a gate electrode of a transistor,wherein the second conductive layer includes a region functioning as a first electrode of a capacitor,wherein the oxide semiconductor layer includes a region functioning as a channel formation region of the transistor,wherein the third conductive layer includes a region functioning as one of a source electrode and a drain electrode of the transistor,wherein the fourth conductive layer includes a region functioning as the other one of the source electrode and the drain electrode of the transistor,wherein the fourth conductive layer is electrically connected to the second conductive layer,wherein the fifth conductive layer includes a region functioning as a second electrode of the capacitor,wherein the oxide semiconductor layer includes In, Ga, and Zn, andwherein a concentration of Zn is lower than a concentration of In or a concentration of Ga.
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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.
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Citations
20 Claims
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1. A semiconductor device comprising:
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a first conductive layer; a second conductive layer; a first insulating layer over the first conductive layer and the second conductive layer; an oxide semiconductor layer over the first insulating layer; a third conductive layer electrically connected to the oxide semiconductor layer; a fourth conductive layer electrically connected to the oxide semiconductor layer; and a fifth conductive layer over the first insulating layer, wherein the first conductive layer includes a region functioning as a gate electrode of a transistor, wherein the second conductive layer includes a region functioning as a first electrode of a capacitor, wherein the oxide semiconductor layer includes a region functioning as a channel formation region of the transistor, wherein the third conductive layer includes a region functioning as one of a source electrode and a drain electrode of the transistor, wherein the fourth conductive layer includes a region functioning as the other one of the source electrode and the drain electrode of the transistor, wherein the fourth conductive layer is electrically connected to the second conductive layer, wherein the fifth conductive layer includes a region functioning as a second electrode of the capacitor, wherein the oxide semiconductor layer includes In, Ga, and Zn, and wherein a concentration of Zn is lower than a concentration of In or a concentration of Ga. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A semiconductor device comprising:
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a first conductive layer; a second conductive layer; a first insulating layer over the first conductive layer and the second conductive layer; a first oxide semiconductor layer over the first insulating layer; a second oxide semiconductor layer over the first insulating layer; a third conductive layer electrically connected to the first oxide semiconductor layer; a fourth conductive layer electrically connected to the first oxide semiconductor layer; a fifth conductive layer electrically connected to the second oxide semiconductor layer; and a sixth conductive layer electrically connected to the second oxide semiconductor layer, wherein the first conductive layer includes a region functioning as a gate electrode of a first transistor, wherein the second conductive layer includes a region functioning as a gate electrode of a second transistor, wherein the first oxide semiconductor layer includes a region functioning as a channel formation region of the first transistor, wherein the second oxide semiconductor layer includes a region functioning as a channel formation region of the second transistor, wherein the region functioning as the channel formation region of the second transistor in the second oxide semiconductor layer includes a first region extending to a channel width direction of the second transistor and a second region extending to the channel width direction of the second transistor, wherein a longer side direction of the first region is substantially parallel to a longer side direction of the second region, wherein the third conductive layer includes a region functioning as one of a source electrode and a drain electrode of the first transistor, wherein the fourth conductive layer includes a region functioning as the other one of the source electrode and the drain electrode of the first transistor, wherein the fourth conductive layer is electrically connected to the second conductive layer, wherein the fifth conductive layer includes a region functioning as one of a source electrode and a drain electrode of the second transistor, wherein the sixth conductive layer includes a region functioning as the other one of the source electrode and the drain electrode of the second transistor, wherein each of the first oxide semiconductor layer and the second oxide semiconductor layer include In, Ga, and Zn, and wherein a concentration of Zn is lower than a concentration of In or a concentration of Ga. - View Dependent Claims (9, 10, 11, 12)
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13. A semiconductor device comprising:
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a first conductive layer; a second conductive layer; a first insulating layer over the first conductive layer and the second conductive layer; a first oxide semiconductor layer over the first insulating layer; a second oxide semiconductor layer over the first insulating layer; a third conductive layer electrically connected to the first oxide semiconductor layer; a fourth conductive layer electrically connected to the first oxide semiconductor layer; a fifth conductive layer electrically connected to the second oxide semiconductor layer; a sixth conductive layer electrically connected to the second oxide semiconductor layer; a second insulating layer over the first oxide semiconductor layer, the second oxide semiconductor layer, the third conductive layer, the fourth conductive layer, the fifth conductive layer, and the sixth conductive layer; and a seventh conductive layer over the second insulating layer, wherein the first conductive layer includes a region functioning as a gate electrode of a first transistor, wherein the second conductive layer includes a region functioning as a gate electrode of a second transistor, wherein the first oxide semiconductor layer includes a region functioning as a channel formation region of the first transistor, wherein the second oxide semiconductor layer includes a region functioning as a channel formation region of the second transistor, wherein the region functioning as the channel formation region of the second transistor of the second oxide semiconductor layer includes a first region extending to a channel width direction of the second transistor and a second region extending to the channel width direction of the second transistor, wherein a longer side direction of the first region is substantially parallel to a longer side direction of the second region, wherein the third conductive layer includes a region functioning as one of a source electrode and a drain electrode of the first transistor, wherein the fourth conductive layer includes a region functioning as the other one of the source electrode and the drain electrode of the first transistor, wherein the fourth conductive layer is electrically connected to the second conductive layer, wherein the fifth conductive layer includes a region functioning as one of a source electrode and a drain electrode of the second transistor, wherein the sixth conductive layer includes a region functioning as the other one of the source electrode and the drain electrode of the second transistor, wherein the seventh conductive layer has a function as a pixel electrode, wherein the seventh conductive layer is electrically connected to the sixth conductive layer, wherein each of the first oxide semiconductor layer and the second oxide semiconductor layer include In, Ga, and Zn, and wherein a concentration of Zn is lower than a concentration of In or a concentration of Ga. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification