Semiconductor device and method for fabricating the same
First Claim
1. A semiconductor device comprising:
- a first oxide insulating layer over a semiconductor substrate;
a first oxide semiconductor layer over the first oxide insulating layer;
a second oxide semiconductor layer over the first oxide semiconductor layer;
a third oxide semiconductor layer over the second oxide semiconductor layer;
a second oxide insulating layer over the third oxide semiconductor layer; and
a first gate electrode layer overlapping with at least the second oxide semiconductor layer with the second oxide insulating layer provided therebetween,wherein the first oxide semiconductor layer, the second oxide semiconductor layer, and the third oxide semiconductor layer each comprise indium,wherein a proportion of indium in the second oxide semiconductor layer is higher than a proportion of indium in each of the first oxide semiconductor layer and the third oxide semiconductor layer,wherein the second oxide semiconductor layer has a crystalline structure,wherein the third oxide semiconductor layer and a side surface of the second oxide semiconductor layer are in contact with each other,wherein the third oxide semiconductor layer and the first oxide semiconductor layer are in contact with each other, andwherein the third oxide semiconductor layer and the first oxide insulating layer are in direct contact with each other.
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Accused Products
Abstract
To provide a highly reliable semiconductor device exhibiting stable electrical characteristics. To fabricate a highly reliable semiconductor device. Included are an oxide semiconductor stack in which a first to a third oxide semiconductor layers are stacked, a source and a drain electrode layers contacting the oxide semiconductor stack, a gate electrode layer overlapping with the oxide semiconductor layer with a gate insulating layer provided therebetween, and a first and a second oxide insulating layers between which the oxide semiconductor stack is sandwiched. The first to the third oxide semiconductor layers each contain indium, gallium, and zinc. The proportion of indium in the second oxide semiconductor layer is higher than that in each of the first and the third oxide semiconductor layers. The first and the third oxide semiconductor layers are each an amorphous semiconductor film. The second oxide semiconductor layer is a crystalline semiconductor film.
183 Citations
24 Claims
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1. A semiconductor device comprising:
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a first oxide insulating layer over a semiconductor substrate; a first oxide semiconductor layer over the first oxide insulating layer; a second oxide semiconductor layer over the first oxide semiconductor layer; a third oxide semiconductor layer over the second oxide semiconductor layer; a second oxide insulating layer over the third oxide semiconductor layer; and a first gate electrode layer overlapping with at least the second oxide semiconductor layer with the second oxide insulating layer provided therebetween, wherein the first oxide semiconductor layer, the second oxide semiconductor layer, and the third oxide semiconductor layer each comprise indium, wherein a proportion of indium in the second oxide semiconductor layer is higher than a proportion of indium in each of the first oxide semiconductor layer and the third oxide semiconductor layer, wherein the second oxide semiconductor layer has a crystalline structure, wherein the third oxide semiconductor layer and a side surface of the second oxide semiconductor layer are in contact with each other, wherein the third oxide semiconductor layer and the first oxide semiconductor layer are in contact with each other, and wherein the third oxide semiconductor layer and the first oxide insulating layer are in direct contact with each other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A semiconductor device comprising:
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a first oxide insulating layer comprising aluminum oxide over a semiconductor substrate; a first oxide semiconductor layer over the first oxide insulating layer; a second oxide semiconductor layer over the first oxide semiconductor layer; a third oxide semiconductor layer over the second oxide semiconductor layer; a second oxide insulating layer over the third oxide semiconductor layer; and a first gate electrode layer overlapping with at least the second oxide semiconductor layer with the second oxide insulating layer provided therebetween, wherein the first oxide semiconductor layer, the second oxide semiconductor layer, and the third oxide semiconductor layer each comprise indium, wherein a proportion of indium in the second oxide semiconductor layer is higher than a proportion of indium in each of the first oxide semiconductor layer and the third oxide semiconductor layer, wherein the third oxide semiconductor layer and a side surface of the second oxide semiconductor layer are in contact with each other, wherein the third oxide semiconductor layer and the first oxide semiconductor layer are in contact with each other, and wherein the third oxide semiconductor layer and the first oxide insulating layer are in direct contact with each other. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification