Semiconductor device
First Claim
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1. A semiconductor device comprising:
- a first transistor over a substrate, the first transistor comprising;
a first gate electrode;
a first insulating layer over the first gate electrode;
a first oxide semiconductor film over the first gate electrode with the first insulating layer interposed therebetween, the first oxide semiconductor film comprising a first channel formation region;
a second oxide semiconductor film on the first semiconductor film;
a second insulating layer over the second oxide semiconductor film;
a second gate electrode over the second oxide semiconductor film with the second insulating layer interposed therebetween; and
a first source electrode and a first drain electrode, wherein each of the first source electrode and the first drain electrode is in contact with the second oxide semiconductor film, anda second transistor over the substrate, the second transistor comprising;
a third oxide semiconductor film over and in contact with the first insulating layer, the third oxide semiconductor film comprising a second channel formation region; and
a third insulating layer over and in contact with the third oxide semiconductor film,wherein each of the first oxide film, the second oxide semiconductor film and the third oxide semiconductor film comprises indium and a second metal element different from indium, andwherein an atomic ratio of indium in the first oxide semiconductor film is larger than an atomic ratio of indium in the second oxide semiconductor film and an atomic ratio of indium in the third oxide semiconductor film.
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Abstract
A semiconductor device provided with a plurality of kinds of transistors with different device structures suitable for functions of circuits is provided. The semiconductor device includes first to third transistors with different device structures over one substrate. A semiconductor layer of the first transistor is an oxide semiconductor film with a stacked-layer structure, and a semiconductor layer of each of the second and third transistors is an oxide semiconductor film with a single-layer structure. Each of the first and second transistors includes a back gate electrode connected to its gate electrode.
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Citations
18 Claims
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1. A semiconductor device comprising:
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a first transistor over a substrate, the first transistor comprising; a first gate electrode; a first insulating layer over the first gate electrode; a first oxide semiconductor film over the first gate electrode with the first insulating layer interposed therebetween, the first oxide semiconductor film comprising a first channel formation region; a second oxide semiconductor film on the first semiconductor film; a second insulating layer over the second oxide semiconductor film; a second gate electrode over the second oxide semiconductor film with the second insulating layer interposed therebetween; and a first source electrode and a first drain electrode, wherein each of the first source electrode and the first drain electrode is in contact with the second oxide semiconductor film, and a second transistor over the substrate, the second transistor comprising; a third oxide semiconductor film over and in contact with the first insulating layer, the third oxide semiconductor film comprising a second channel formation region; and a third insulating layer over and in contact with the third oxide semiconductor film, wherein each of the first oxide film, the second oxide semiconductor film and the third oxide semiconductor film comprises indium and a second metal element different from indium, and wherein an atomic ratio of indium in the first oxide semiconductor film is larger than an atomic ratio of indium in the second oxide semiconductor film and an atomic ratio of indium in the third oxide semiconductor film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 15)
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10. A semiconductor device comprising:
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a first transistor over a substrate, the first transistor comprising; a first gate electrode; a first insulating layer over the first gate electrode; a first oxide semiconductor film over the first gate electrode with the first insulating layer interposed therebetween, the first oxide semiconductor film comprising a first channel formation region; a second oxide semiconductor film on the first semiconductor film; a third oxide semiconductor film on the second semiconductor film; a second insulating layer over the third oxide semiconductor film; a second gate electrode over the third oxide semiconductor film with the second insulating layer interposed therebetween; and a first source electrode and a first drain electrode, wherein each of the first source electrode and the first drain electrode is in contact with the third oxide semiconductor film, and a second transistor over the substrate, the second transistor comprising; a fourth oxide semiconductor film over and in contact with the first insulating layer, the fourth oxide semiconductor film comprising a second channel formation region; and a third insulating layer over and in contact with the fourth oxide semiconductor film, wherein each of the first oxide semiconductor film, the second oxide semiconductor film, the third oxide semiconductor film, and the fourth oxide semiconductor film comprises indium and a second metal element different from indium, and wherein an atomic ratio of indium in the second oxide semiconductor film is larger than an atomic ratio of indium in the first oxide semiconductor film, an atomic ratio of indium in the third oxide semiconductor film, and an atomic ratio of indium in the fourth oxide semiconductor film. - View Dependent Claims (11, 12, 13, 14, 16, 17, 18)
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Specification