Semiconductor device
First Claim
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1. A semiconductor device comprising:
- a gate electrode layer;
a gate insulating layer over the gate electrode layer;
an oxide semiconductor stacked layer overlapping with the gate electrode layer with the gate insulating layer therebetween; and
a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor stacked layer,wherein the oxide semiconductor stacked layer comprises;
a first oxide semiconductor layer in contact with the gate insulating layer;
a second oxide semiconductor layer containing an impurity imparting n-type conductivity on and in contact with the first oxide semiconductor layer; and
a third oxide semiconductor layer on and in contact with the second oxide semiconductor layer, andwherein the first oxide semiconductor layer and the third oxide semiconductor layer are i-type oxide semiconductor layers.
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Abstract
High field-effect mobility is provided for a transistor including an oxide semiconductor. Further, a highly reliable semiconductor device including the transistor is provided. In a bottom-gate transistor including an oxide semiconductor layer, an oxide semiconductor layer functioning as a current path (channel) of the transistor is sandwiched between oxide semiconductor layers having lower carrier densities than the oxide semiconductor layer. In such a structure, the channel is formed away from the interface of the oxide semiconductor stacked layer with an insulating layer in contact with the oxide semiconductor stacked layer, i.e., a buried channel is formed.
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Citations
17 Claims
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1. A semiconductor device comprising:
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a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor stacked layer overlapping with the gate electrode layer with the gate insulating layer therebetween; and a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor stacked layer, wherein the oxide semiconductor stacked layer comprises; a first oxide semiconductor layer in contact with the gate insulating layer; a second oxide semiconductor layer containing an impurity imparting n-type conductivity on and in contact with the first oxide semiconductor layer; and a third oxide semiconductor layer on and in contact with the second oxide semiconductor layer, and wherein the first oxide semiconductor layer and the third oxide semiconductor layer are i-type oxide semiconductor layers. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A semiconductor device comprising:
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a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor stacked layer overlapping with the gate electrode layer with the gate insulating layer therebetween; and a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor stacked layer, wherein the oxide semiconductor stacked layer comprises; a first oxide semiconductor layer in contact with the gate insulating layer; a second oxide semiconductor layer containing an impurity imparting n-type conductivity on and in contact with the first oxide semiconductor layer; and a third oxide semiconductor layer on and in contact with the second oxide semiconductor layer, wherein the first to third oxide semiconductor layers include a same metal element, and wherein the first oxide semiconductor layer and the third oxide semiconductor layer are i-type oxide semiconductor layers. - View Dependent Claims (9, 10, 11)
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12. A display device comprising:
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a gate electrode layer; a gate insulating layer over the gate electrode layer; an oxide semiconductor stacked layer overlapping with the gate electrode layer with the gate insulating layer therebetween; a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor stacked layer, and a pixel electrode electrically connected to the drain electrode layer, wherein the oxide semiconductor stacked layer comprises; a first oxide semiconductor layer in contact with the gate insulating layer; a second oxide semiconductor layer containing an impurity imparting n-type conductivity on and in contact with the first oxide semiconductor layer; and a third oxide semiconductor layer on and in contact with the second oxide semiconductor layer, and wherein the first oxide semiconductor layer and the third oxide semiconductor layer are i-type oxide semiconductor layers. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification