SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF
First Claim
1. A semiconductor device comprising:
- a gate electrode layer over an insulating surface;
a gate insulating layer over the gate electrode layer;
an oxide semiconductor layer over the gate insulating layer, the oxide semiconductor layer including a channel formation region overlapping with the gate electrode layer;
an oxide insulating layer over the gate electrode layer with the oxide semiconductor layer interposed therebetween, the oxide insulating layer being in contact with a first region of the oxide semiconductor layer;
a source electrode layer and a drain electrode layer over the oxide semiconductor layer; and
an insulating layer over the source electrode layer and the drain electrode layer,wherein the oxide semiconductor layer comprises a second region in contact with the source electrode layer or the drain electrode layer, and a third region in contact with the insulating layer, andwherein the third region is located between the first region and the second region.
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Abstract
An object is to provide a semiconductor device having a structure in which parasitic capacitance between wirings can be efficiently reduced. In a bottom gate thin film transistor using an oxide semiconductor layer, an oxide insulating layer used as a channel protection layer is formed above and in contact with part of the oxide semiconductor layer overlapping with a gate electrode layer, and at the same time an oxide insulating layer covering a peripheral portion (including a side surface) of the stacked oxide semiconductor layer is formed. Further, a source electrode layer and a drain electrode layer are formed in a manner such that they do not overlap with the channel protection layer. Thus, a structure in which an insulating layer over the source electrode layer and the drain electrode layer is in contact with the oxide semiconductor layer is provided.
258 Citations
27 Claims
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1. A semiconductor device comprising:
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a gate electrode layer over an insulating surface; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer, the oxide semiconductor layer including a channel formation region overlapping with the gate electrode layer; an oxide insulating layer over the gate electrode layer with the oxide semiconductor layer interposed therebetween, the oxide insulating layer being in contact with a first region of the oxide semiconductor layer; a source electrode layer and a drain electrode layer over the oxide semiconductor layer; and an insulating layer over the source electrode layer and the drain electrode layer, wherein the oxide semiconductor layer comprises a second region in contact with the source electrode layer or the drain electrode layer, and a third region in contact with the insulating layer, and wherein the third region is located between the first region and the second region. - View Dependent Claims (3, 5, 7, 9, 11, 13, 15, 17, 19, 21)
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2. A semiconductor device comprising:
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a gate electrode layer over an insulating surface; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; an oxide insulating layer over the oxide semiconductor layer; a source electrode layer and a drain electrode layer over the oxide semiconductor layer; and an insulating layer over the source electrode layer and the drain electrode layer, wherein the oxide semiconductor layer comprises a first region in contact with the oxide insulating layer, a second region in contact with the source electrode layer or the drain electrode layer, and a third region in contact with the insulating layer, wherein, in the first region, a channel formation region overlaps with the gate electrode layer with the gate insulating layer interposed therebetween, and wherein the third region is located between the channel formation region and the second region. - View Dependent Claims (4, 6, 8, 10, 12, 14, 16, 18, 20, 22)
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23. A method of forming a semiconductor device, comprising the steps of:
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forming a gate insulating layer over a gate electrode layer; forming an oxide semiconductor layer over the gate insulating layer; dehydrating or dehydrogenating the oxide semiconductor layer; forming an oxide insulating layer being in contact with part of the oxide semiconductor layer and covering a peripheral portion and a side surface of the oxide semiconductor layer; forming a source electrode layer and a drain electrode layer over the oxide insulating layer; and forming an insulating layer in contact with the oxide insulating layer, the source electrode layer, the drain electrode layer, and the oxide semiconductor layer, wherein the oxide semiconductor layer is prevented from being exposed to air between the step of dehydrating or dehydrogenating the oxide semiconductor layer and the step of forming the oxide insulating layer, so as to prevent water or hydrogen contamination. - View Dependent Claims (24, 25, 26, 27)
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Specification