Semiconductor device

Abstract

To provide a transistor including an oxide semiconductor film in which the variation in electrical characteristic is suppressed.SOLUTION: A transistor 100 includes a first gate electrode 104, a first insulating film 106 thereon, an oxide semiconductor film 108 thereon, a source electrode 112a and a drain electrode 112b electrically connected to the oxide semiconductor film, second insulating films 114 and 116 on the oxide semiconductor film, a second gate electrode 120b thereon, and a third insulating film 118 thereon. The oxide semiconductor film includes a first oxide semiconductor film 108a on the first gate electrode side, and a second oxide semiconductor film 108b on the first oxide semiconductor film. The first oxide semiconductor film and the second oxide semiconductor film contain In, M (M is Al, Ga, Y, or Sn) and Zn. The second oxide semiconductor film includes a region where the atomic number of In is less than that in the first oxide semiconductor film. The second gate electrode contains at least one metal element included in the oxide semiconductor film.SELECTED DRAWING: Figure 1

Claims

[Claim 1] A semiconductor device having a transistor, The transistor is A first gate electrode; a first insulating film on the first gate electrode; an oxide semiconductor film on the first insulating film; a source electrode electrically connected to the oxide semiconductor film; a drain electrode electrically connected to the oxide semiconductor film; a second insulating film on the oxide semiconductor film; a second gate electrode on the second insulating film; a third insulating film on the second gate electrode; The oxide semiconductor film is a first oxide semiconductor film on the first gate electrode side; a second oxide semiconductor film over the first oxide semiconductor film, the first oxide semiconductor film and the second oxide semiconductor film contain In, M (M is Al, Ga, Y, or Sn), and Zn, the second oxide semiconductor film has a region having a smaller number of In atoms than the first oxide semiconductor film, the second gate electrode includes at least one metal element contained in the oxide semiconductor film.

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