Semiconductor device and method for manufacturing the same
First Claim
1. A semiconductor device comprising:
- a first non-single crystalline oxide semiconductor layer comprising indium on an insulating surface, the first non-single crystalline oxide semiconductor layer having a first conductivity;
a second non-single crystalline oxide semiconductor layer comprising indium over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having a second conductivity lower than the first conductivity;
a gate electrode, wherein the gate electrode is overlapped with the first non-single crystalline oxide semiconductor layer and the second non-single crystalline oxide semiconductor layer; and
an insulating film on the second non-single crystalline oxide semiconductor layer.
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Abstract
An object is, in a thin film transistor in which an oxide semiconductor is used as an active layer, to prevent change in composition, film quality, an interface, or the like of an oxide semiconductor region serving as an active layer, and to stabilize electrical characteristics of the thin film transistor. In a thin film transistor in which a first oxide semiconductor region is used as an active layer, a second oxide semiconductor region having lower electrical conductivity than the first oxide semiconductor region is formed between the first oxide semiconductor region and a protective insulating layer for the thin film transistor, whereby the second oxide semiconductor region serves as a protective layer for the first oxide semiconductor region; thus, change in composition or deterioration in film quality of the first oxide semiconductor region can be prevented, and electrical characteristics of the thin film transistor can be stabilized.
166 Citations
42 Claims
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1. A semiconductor device comprising:
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a first non-single crystalline oxide semiconductor layer comprising indium on an insulating surface, the first non-single crystalline oxide semiconductor layer having a first conductivity; a second non-single crystalline oxide semiconductor layer comprising indium over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having a second conductivity lower than the first conductivity; a gate electrode, wherein the gate electrode is overlapped with the first non-single crystalline oxide semiconductor layer and the second non-single crystalline oxide semiconductor layer; and an insulating film on the second non-single crystalline oxide semiconductor layer. - View Dependent Claims (7, 8, 9, 10, 11, 12, 40, 42)
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2. A semiconductor device comprising:
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a first non-single crystalline oxide semiconductor layer comprising indium on an insulating surface, the first non-single crystalline oxide semiconductor layer having a first conductivity; a second non-single crystalline oxide semiconductor layer comprising indium over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having a second conductivity lower than the first conductivity; a gate electrode, wherein the gate electrode is overlapped with the first non-single crystalline oxide semiconductor layer and the second non-single crystalline oxide semiconductor layer; and an insulating film on the second non-single crystalline oxide semiconductor layer, wherein a concentration of sodium in the first non-single crystalline oxide semiconductor layer is 5×
1019/cm3 or lower. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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3. A semiconductor device comprising:
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a first non-single crystalline oxide semiconductor layer comprising indium on an insulating surface, the first non-single crystalline oxide semiconductor layer having a first conductivity; a second non-single crystalline oxide semiconductor layer comprising indium over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having a second conductivity lower than the first conductivity; a gate electrode, wherein the gate electrode is overlapped with the first non-single crystalline oxide semiconductor layer and the second non-single crystalline oxide semiconductor layer; and an insulating film on the second non-single crystalline oxide semiconductor layer; a source electrode in electrical contact with the first non-single crystalline oxide semiconductor layer through a first buffer region having n-type conductivity; a drain electrode in electrical contact with the first non-single crystalline oxide semiconductor layer through a second buffer region having n-type conductivity, wherein each of the first buffer region and the second buffer region comprises crystal grains of an oxide semiconductor material comprising indium. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 41)
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4. A display device comprising:
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a gate electrode over a substrate; a gate insulating film over the gate electrode; a first non-single crystalline oxide semiconductor layer comprising indium over the gate electrode with the gate insulating film interposed therebetween, the first non-single crystalline oxide semiconductor layer having a first conductivity; a second non-single crystalline oxide semiconductor layer comprising indium over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having a second conductivity lower than the first conductivity; an insulating film on the second non-single crystalline oxide semiconductor layer; a source electrode in electrical contact with the first non-single crystalline oxide semiconductor layer through a first buffer region having n-type conductivity; a drain electrode in electrical contact with the first non-single crystalline oxide semiconductor layer through a second buffer region having n-type conductivity; and a pixel electrode in electrical contact with one of the source electrode and the drain electrode, wherein each of the first buffer region and the second buffer region comprises crystal grains of an oxide semiconductor material comprising indium and oxygen. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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5. A display device comprising:
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a gate electrode over a substrate; a gate insulating film over the gate electrode; a first non-single crystalline oxide semiconductor layer comprising indium over the gate electrode with the gate insulating film interposed therebetween, the first non-single crystalline oxide semiconductor layer having a first conductivity; a second non-single crystalline oxide semiconductor layer comprising indium over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having a second conductivity lower than the first conductivity; an insulating film on the second non-single crystalline oxide semiconductor layer; and a pixel electrode in electrical contact with the first non-single crystalline oxide semiconductor layer, wherein the gate electrode completely overlaps the first non-single crystalline oxide semiconductor layer and the second non-single crystalline oxide semiconductor layer. - View Dependent Claims (32, 33, 34, 35, 36)
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6. A display device comprising:
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a gate electrode over a substrate; a gate insulating film over the gate electrode; a first non-single crystalline oxide semiconductor layer comprising indium over the gate electrode with the gate insulating film interposed therebetween, the first non-single crystalline oxide semiconductor layer having a first conductivity; a second non-single crystalline oxide semiconductor layer comprising indium over the first non-single crystalline oxide semiconductor layer, the second non-single crystalline oxide semiconductor layer having a second conductivity lower than the first conductivity; a first insulating film comprising silicon and oxygen on the second non-single crystalline oxide semiconductor layer; a second insulating film comprising silicon and nitrogen over the first insulating film; and a planarizing insulating film comprising an organic material over the second insulating film; a pixel electrode over the planarizing insulating film, the pixel electrode being in electrical contact with the first non-single crystalline oxide semiconductor layer. - View Dependent Claims (37, 38, 39)
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Specification