Semiconductor device
First Claim
1. A semiconductor device comprising:
- a first transistor comprising;
a first oxide semiconductor layer;
a first insulating layer over the first oxide semiconductor layer; and
a first gate electrode over the first oxide semiconductor layer with the first insulating layer interposed therebetween; and
a second transistor comprising;
a second oxide semiconductor layer;
the first insulating layer over the second oxide semiconductor layer; and
a second gate electrode over the second oxide semiconductor layer with the first insulating layer interposed therebetween,wherein the first oxide semiconductor layer and the second oxide semiconductor layer each comprise a plurality of crystals of an oxide semiconductor in channel regions,wherein c-axes of the plurality of crystals of the oxide semiconductor are aligned to each other in the channel regions, andwherein an oxygen concentration in the first oxide semiconductor layer is higher than that in the second oxide semiconductor layer.
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Accused Products
Abstract
A semiconductor device which can operate at high speed and consumes a smaller amount of power is provided. In a semiconductor device including transistors each including an oxide semiconductor, the oxygen concentration of the oxide semiconductor film of the transistor having small current at negative gate voltage is different from that of the oxide semiconductor film of the transistor having high field-effect mobility and large on-state current. Typically, the oxygen concentration of the oxide semiconductor film of the transistor having high field-effect mobility and large on-state current is lower than that of the oxide semiconductor film of the transistor having small current at negative gate voltage.
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Citations
14 Claims
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1. A semiconductor device comprising:
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a first transistor comprising; a first oxide semiconductor layer; a first insulating layer over the first oxide semiconductor layer; and a first gate electrode over the first oxide semiconductor layer with the first insulating layer interposed therebetween; and a second transistor comprising; a second oxide semiconductor layer; the first insulating layer over the second oxide semiconductor layer; and a second gate electrode over the second oxide semiconductor layer with the first insulating layer interposed therebetween, wherein the first oxide semiconductor layer and the second oxide semiconductor layer each comprise a plurality of crystals of an oxide semiconductor in channel regions, wherein c-axes of the plurality of crystals of the oxide semiconductor are aligned to each other in the channel regions, and wherein an oxygen concentration in the first oxide semiconductor layer is higher than that in the second oxide semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A semiconductor device comprising:
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a first transistor comprising; a first gate electrode; a first oxide semiconductor layer overlapping with the first gate electrode with a first insulating layer interposed therebetween; and a second transistor comprising; a second gate electrode; and a second oxide semiconductor layer overlapping with the second gate electrode with the first insulating layer interposed therebetween, wherein the first oxide semiconductor layer and the second oxide semiconductor layer each comprise a plurality of crystals of an oxide semiconductor in channel regions, wherein c-axes of the plurality of crystals of the oxide semiconductor are aligned to each other in the channel regions, and wherein an oxygen concentration in the first oxide semiconductor layer is higher than that in the second oxide semiconductor layer. - View Dependent Claims (11, 12, 13, 14)
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Specification