Semiconductor device and display device including the semiconductor device
First Claim
1. A semiconductor device comprising:
- a transistor comprising;
an oxide semiconductor film;
a first gate electrode, the oxide semiconductor film overlapping with the first gate electrode;
a first gate insulating film between the oxide semiconductor film and the first gate electrode;
a source electrode electrically connected to the oxide semiconductor film; and
a drain electrode electrically connected to the oxide semiconductor film,wherein the oxide semiconductor film comprises;
a first oxide semiconductor film in contact with the first gate insulating film; and
a second oxide semiconductor film in contact with the first oxide semiconductor film,wherein an atomic proportion of In in the first oxide semiconductor film is larger than an atomic proportion of M in the first oxide semiconductor film,wherein M is Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf,wherein an atomic proportion of In in the second oxide semiconductor film is smaller than the atomic proportion of In in the first oxide semiconductor film,wherein the oxide semiconductor film comprises a first region overlapping with the first gate electrode, a second region overlapping with the source electrode, and a third region overlapping with the drain electrode,wherein the first region does not comprise the second region and the third region,wherein the first oxide semiconductor film has a first thickness,wherein the second oxide semiconductor film has a second thickness overlapped with the first gate electrode and a third thickness overlapped with the source electrode and the drain electrode,wherein the third thickness is larger than the first thickness, andwherein the first thickness is larger than the second thickness.
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Accused Products
Abstract
To reduce parasitic capacitance in a semiconductor device having a transistor including an oxide semiconductor. The transistor includes a first gate electrode, a first gate insulating film over the first gate electrode, an oxide semiconductor film over the first gate insulating film, and source and drain electrodes electrically connected to the oxide semiconductor film. The oxide semiconductor film includes a first oxide semiconductor film on the first gate electrode side and a second oxide semiconductor film over the first oxide semiconductor film. The atomic proportion of In is larger than the atomic proportion of M (M is Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf) in the first oxide semiconductor film, and the atomic proportion of In in the second oxide semiconductor film is smaller than that in the first oxide semiconductor film.
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Citations
30 Claims
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1. A semiconductor device comprising:
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a transistor comprising; an oxide semiconductor film; a first gate electrode, the oxide semiconductor film overlapping with the first gate electrode; a first gate insulating film between the oxide semiconductor film and the first gate electrode; a source electrode electrically connected to the oxide semiconductor film; and a drain electrode electrically connected to the oxide semiconductor film, wherein the oxide semiconductor film comprises; a first oxide semiconductor film in contact with the first gate insulating film; and a second oxide semiconductor film in contact with the first oxide semiconductor film, wherein an atomic proportion of In in the first oxide semiconductor film is larger than an atomic proportion of M in the first oxide semiconductor film, wherein M is Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf, wherein an atomic proportion of In in the second oxide semiconductor film is smaller than the atomic proportion of In in the first oxide semiconductor film, wherein the oxide semiconductor film comprises a first region overlapping with the first gate electrode, a second region overlapping with the source electrode, and a third region overlapping with the drain electrode, wherein the first region does not comprise the second region and the third region, wherein the first oxide semiconductor film has a first thickness, wherein the second oxide semiconductor film has a second thickness overlapped with the first gate electrode and a third thickness overlapped with the source electrode and the drain electrode, wherein the third thickness is larger than the first thickness, and wherein the first thickness is larger than the second thickness. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A semiconductor device comprising:
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a transistor comprising; a first gate electrode; a first gate insulating film over the first gate electrode; an oxide semiconductor film over the first gate insulating film; a source electrode electrically connected to the oxide semiconductor film; a drain electrode electrically connected to the oxide semiconductor film; a second gate insulating film over the oxide semiconductor film; and a second gate electrode over the second gate insulating film, wherein the oxide semiconductor film comprises; a first oxide semiconductor film; and a second oxide semiconductor film over the first oxide semiconductor film, wherein an atomic proportion of In in the first oxide semiconductor film is larger than an atomic proportion of M in the first oxide semiconductor film, wherein M is Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf, wherein an atomic proportion of In in the second oxide semiconductor film is smaller than the atomic proportion of In in the first oxide semiconductor film, wherein the oxide semiconductor film comprises a first region overlapping with the first gate electrode, a second region overlapping with the source electrode, a third region overlapping with the drain electrode, and a fourth region overlapping with the second gate electrode, wherein the first region or the fourth region does not comprise the second region and the third region, wherein the first oxide semiconductor film has a first thickness, wherein the second oxide semiconductor film has a second thickness overlapped with the first gate electrode and a third thickness overlapped with the source electrode and the drain electrode, wherein the third thickness is larger than the first thickness, and wherein the first thickness is larger than the second thickness. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A semiconductor device comprising:
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a transistor comprising; a first gate electrode; a first gate insulating film over the first gate electrode; an oxide semiconductor film over the first gate insulating film; a source electrode electrically connected to the oxide semiconductor film; a drain electrode electrically connected to the oxide semiconductor film; a second gate insulating film over the oxide semiconductor film; and a second gate electrode over the second gate insulating film, wherein the oxide semiconductor film comprises; a first oxide semiconductor film; and a second oxide semiconductor film over the first oxide semiconductor film, wherein an atomic proportion of In in the first oxide semiconductor film is larger than an atomic proportion of M in the first oxide semiconductor film, wherein M is Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or I-If, wherein an atomic proportion of In in the second oxide semiconductor film is smaller than the atomic proportion of In in the first oxide semiconductor film, wherein the oxide semiconductor film comprises a first region overlapping with the first gate electrode, a second region overlapping with the source electrode, a third region overlapping with the drain electrode, and a fourth region overlapping with the second gate electrode, wherein the first region or the fourth region does not comprise the second region or the third region, wherein the first oxide semiconductor film has a first thickness, wherein the second oxide semiconductor film has a second thickness overlapped with the first gate electrode and a third thickness overlapped with the source electrode and the drain electrode, wherein the third thickness is larger than the first thickness, and wherein the first thickness is larger than the second thickness. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. A display device comprising:
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an oxide semiconductor film; a first gate electrode, the oxide semiconductor film overlapping with the first gate electrode; a first gate insulating film between the oxide semiconductor film and the first gate electrode; a source electrode electrically connected to the oxide semiconductor film; and a drain electrode electrically connected to the oxide semiconductor film, wherein the oxide semiconductor film comprises; a first oxide semiconductor film in contact with the first gate insulating film; a second oxide semiconductor film in contact with the first oxide semiconductor film; and a conductive film electrically connected to one of the source electrode and the drain electrode, wherein an atomic proportion of In in the first oxide semiconductor film is larger than an atomic proportion of M in the first oxide semiconductor film, wherein M is Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf, wherein the oxide semiconductor film comprises a first region overlapping with the first gate electrode, a second region overlapping with the source electrode, and a third region overlapping with the drain electrode, wherein the first oxide semiconductor film has a first thickness, wherein the second oxide semiconductor film has a second thickness overlapped with the first gate electrode and a third thickness overlapped with the source electrode and the drain electrode, wherein the third thickness is larger than the first thickness, and wherein the first thickness is larger than the second thickness. - View Dependent Claims (27, 28, 29, 30)
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Specification