Semiconductor device
First Claim
1. A semiconductor device comprising:
- a first insulating film comprising a first region, a second region, and a third region between the first region and the second region, wherein a thickness of the first insulating film in the third region is thicker than a thickness of the first region of the first insulating film and a thickness of the second region of the second region;
a first oxide semiconductor film over the third region of the first insulating film;
a second oxide semiconductor film over and in contact with the first oxide semiconductor film;
a third oxide semiconductor film over and in contact with the second oxide semiconductor film;
a second insulating film over the third oxide semiconductor film;
a second gate electrode over the second insulating film and the first region and the second region of the first insulating film; and
a first electrode and a second electrode each electrically connected to the second oxide semiconductor film,wherein a bottom surface of the second gate electrode is positioned lower than a bottom surface of the second oxide semiconductor film so that the second gate electrode faces a side surface of the second oxide semiconductor film with the second insulating film interposed therebetween.
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Abstract
A semiconductor device which includes an oxide semiconductor and in which formation of a parasitic channel due to a gate BT stress is suppressed is provided. Further, a semiconductor device including a transistor having excellent electrical characteristics is provided. The semiconductor device includes a transistor having a dual-gate structure in which an oxide semiconductor film is provided between a first gate electrode and a second gate electrode; gate insulating films are provided between the oxide semiconductor film and the first gate electrode and between the oxide semiconductor film and the second gate electrode; and in the channel width direction of the transistor, the first or second gate electrode faces a side surface of the oxide semiconductor film with the gate insulating film between the oxide semiconductor film and the first or second gate electrode.
168 Citations
16 Claims
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1. A semiconductor device comprising:
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a first insulating film comprising a first region, a second region, and a third region between the first region and the second region, wherein a thickness of the first insulating film in the third region is thicker than a thickness of the first region of the first insulating film and a thickness of the second region of the second region; a first oxide semiconductor film over the third region of the first insulating film; a second oxide semiconductor film over and in contact with the first oxide semiconductor film; a third oxide semiconductor film over and in contact with the second oxide semiconductor film; a second insulating film over the third oxide semiconductor film; a second gate electrode over the second insulating film and the first region and the second region of the first insulating film; and a first electrode and a second electrode each electrically connected to the second oxide semiconductor film, wherein a bottom surface of the second gate electrode is positioned lower than a bottom surface of the second oxide semiconductor film so that the second gate electrode faces a side surface of the second oxide semiconductor film with the second insulating film interposed therebetween. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A semiconductor device comprising:
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a first insulating film comprising a first region, a second region, and a third region between the first region and the second region, wherein a thickness of the first insulating film in the third region is thicker than a thickness of the first region of the first insulating film and a thickness of the second region of the second region; a second oxide semiconductor film over the third region of the first insulating film; a third oxide semiconductor film over and in contact with the second oxide semiconductor film; a second insulating film over the third oxide semiconductor film; a second gate electrode over the second insulating film and the first region and the second region of the first insulating film; and a first electrode and a second electrode each electrically connected to the second oxide semiconductor film, wherein a bottom surface of the second gate electrode is positioned lower than a bottom surface of the second oxide semiconductor film so that the second gate electrode faces a side surface of the second oxide semiconductor film with the second insulating film interposed therebetween. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification