Abstract: The reliability of a transistor including an oxide semiconductor can be improved by suppressing a change in electrical characteristics. A transistor included in a semiconductor device includes a first oxide semiconductor film over a first insulating film, a gate insulating film over the first oxide semiconductor film, a second oxide semiconductor film over the gate insulating film, and a second insulating film over the first oxide semiconductor film and the second oxide semiconductor film. The first oxide semiconductor film includes a channel region in contact with the gate insulating film, a source region in contact with the second insulating film, and a drain region in contact with the second insulating film. The second oxide semiconductor film has a higher carrier density than the first oxide semiconductor film.

Abstract: A semiconductor device having favorable and stable electrical characteristics is provided. The semiconductor device includes a first and a second transistor over an insulating surface. The first and the second transistors each include a first insulating layer, a semiconductor layer over the first insulating layer, a second insulating layer over the semiconductor layer, and a first conductive layer overlapping with the semiconductor layer with the second insulating layer interposed therebetween. The first insulating layer includes a convex first region that overlaps with the semiconductor layer and a second region that does not and is thinner than the first region. The first conductive layer includes a part over the second region where a lower surface of the first conductive layer is positioned below a lower surface of the semiconductor layer. The second transistor further includes a third conductive layer overlapping with the semiconductor layer with the first insulating layer interposed therebetween.

Abstract: A semiconductor device with favorable electrical characteristics is provided. A highly reliable semiconductor device is provided. A semiconductor device with stable electrical characteristics is provided. The semiconductor device includes a first insulating layer, a second insulating layer, a semiconductor layer, and a first conductive layer. The semiconductor layer, the second insulating layer, and the first conductive layer are stacked in this order over the first insulating layer. The first insulating layer has a stacked-layer structure in which a first insulating film, a second insulating film, and a third insulating film are stacked in this order. The second insulating layer includes an oxide. The third insulating film includes a part in contact with the semiconductor layer. The first insulating film includes silicon and nitrogen. The second insulating film includes silicon, nitrogen, and oxygen. The third insulating film includes silicon and oxygen. The semiconductor layer includes indium and oxygen.

Abstract: A semiconductor device having favorable electrical characteristics is provided. The semiconductor device is manufactured by a first step of forming a semiconductor layer containing a metal oxide, a second step of forming a first insulating layer, a third step of forming a first conductive film over the first insulating layer, a fourth step of etching part of the first conductive film to form a first conductive layer, thereby forming a first region over the semiconductor layer that overlaps with the first conductive layer and a second region over the semiconductor layer that does not overlap with the first conductive layer, and a fifth step of performing first treatment on the conductive layer. The first treatment is plasma treatment in an atmosphere including a mixed gas of a first gas containing an oxygen element but not containing a hydrogen element, and a second gas containing a hydrogen element but not containing an oxygen element.

Abstract: In a transistor that includes an oxide semiconductor, a change in electrical characteristics is suppressed and the reliability is improved. A semiconductor device that includes a transistor is provided. The transistor includes a first conductive film that functions as a first gate electrode, a first gate insulating film, a first oxide semiconductor film that includes a channel region, a second gate insulating film, and a second oxide semiconductor film and a second conductive film that function as a second gate electrode. The second oxide semiconductor film includes a region higher in carrier density than the first oxide semiconductor film. The second conductive film includes a region in contact with the first conductive film.

Abstract: A novel material is provided. A composite oxide semiconductor includes a first region and a second region. The first region contains indium. The second region contains an element M (the element M is one or more of Ga, Al, Hf, Y, and Sn). The first region and the second region are arranged in a mosaic pattern. The composite oxide semiconductor further includes a third region. The element M is gallium. The first region contains indium oxide or indium zinc oxide. The second region contains gallium oxide or gallium zinc oxide. The third region contains zinc oxide.

Abstract: To suppress a change in electrical characteristics and to improve reliability in a semiconductor device using a transistor including an oxide semiconductor. The semiconductor device includes a gate electrode over an insulating surface, an oxide semiconductor film overlapping with the gate electrode, a gate insulating film which is between the gate electrode and the oxide semiconductor film and is in contact with a surface of the oxide semiconductor film, a protective film in contact with an opposite surface of the surface of the oxide semiconductor film, and a pair of electrodes in contact with the oxide semiconductor film. In the gate insulating film or the protective film, the amount of gas having a mass-to-charge ratio m/z of 17 released by heat treatment is greater than the amount of nitrogen oxide released by heat treatment.

Abstract: A semiconductor device including an oxide semiconductor in which on-state current is high is provided. The semiconductor device includes a first transistor provided in a driver circuit portion and a second transistor provided in a pixel portion; the first transistor and the second transistor are transistors having a top-gate structure. In an oxide semiconductor film of each of the transistors, an impurity element is contained in regions which do not overlap with a gate electrode. The regions of the oxide regions. Furthermore, the regions of the oxide semiconductor film which contain the impurity element are in contact with a film containing hydrogen. The first transistor provided in the driver circuit portion includes two gate electrodes between which the oxide semiconductor film is provided.

Abstract: A semiconductor device having favorable characteristics is provided. A semiconductor device having stable electrical characteristics is provided. An island-shaped insulating layer containing an oxide is provided in contact with a bottom surface of a semiconductor layer containing a metal oxide that exhibits semiconductor characteristics. The insulating layer containing an oxide is provided in contact with a portion of the semiconductor layer to be a channel formation region and is not provided under portions to be low-resistance regions.

Abstract: The reliability of a transistor including an oxide semiconductor can be improved by suppressing a change in electrical characteristics. A transistor included in a semiconductor device includes a first oxide semiconductor film over a first insulating film, a gate insulating film over the first oxide semiconductor film, a second oxide semiconductor film over the gate insulating film, and a second insulating film over the first oxide semiconductor film and the second oxide semiconductor film. The first oxide semiconductor film includes a channel region in contact with the gate insulating film, a source region in contact with the second insulating film, and a drain region in contact with the second insulating film. The second oxide semiconductor film has a higher carrier density than the first oxide semiconductor film.

Abstract: A semiconductor device that can be highly integrated is provided. The semiconductor device includes a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, a first insulating layer, a second insulating layer, a third insulating layer, a fourth insulating layer, a first conductive layer, and a second conductive layer. The second semiconductor layer is positioned over the first semiconductor layer, the second conductive layer is positioned on the second semiconductor layer, and the second insulating layer is provided so as to cover a top surface and a side surface of the second conductive layer. The second conductive layer and the second insulating layer include a first opening, and the third semiconductor layer is provided in contact with a top surface of the second insulating layer, a side surface of the first opening, and the second semiconductor layer.

Abstract: The reliability of a transistor including an oxide semiconductor can be improved by suppressing a change in electrical characteristics. A transistor included in a semiconductor device includes a first oxide semiconductor film over a first insulating film, a gate insulating film over the first oxide semiconductor film, a second oxide semiconductor film over the gate insulating film, and a second insulating film over the first oxide semiconductor film and the second oxide semiconductor film. The first oxide semiconductor film includes a channel region in contact with the gate insulating film, a source region in contact with the second insulating film, and a drain region in contact with the second insulating film. The second oxide semiconductor film has a higher carrier density than the first oxide semiconductor film.

Abstract: A novel material is provided. A composite oxide semiconductor includes a first region and a second region. The first region contains indium. The second region contains an element M (the element M is one or more of Ga, Al, Hf, Y, and Sn). The first region and the second region are arranged in a mosaic pattern. The composite oxide semiconductor further includes a third region. The element M is gallium. The first region contains indium oxide or indium zinc oxide. The second region contains gallium oxide or gallium zinc oxide. The third region contains zinc oxide.

Abstract: A semiconductor device comprising a pixel portion comprising a capacitor and a transistor is provided. The capacitor comprises a first oxide semiconductor film and a transparent conductive material. The transistor comprises a second oxide semiconductor film, a source electrode, and a drain electrode. The transistor is electrically connected to the capacitor. The capacitor is provided to overlap with a first opening portion in an insulating film and a second opening portion in an organic resin film. The transparent conductive material comprises a region over the organic resin film. The second oxide semiconductor film comprises a channel formation region and a first region outside the channel formation region. Each of a carrier density of the first oxide semiconductor film and a carrier density of the first region is higher than a carrier density of the channel formation region.

Abstract: To improve field-effect mobility and reliability in a transistor including an oxide semiconductor film. A semiconductor device includes a transistor including an oxide semiconductor film. The transistor includes a region where the maximum value of field-effect mobility of the transistor at a gate voltage of higher than 0 V and lower than or equal to 10 V is larger than or equal to 40 and smaller than 150; a region where the threshold voltage is higher than or equal to minus 1 V and lower than or equal to 1 V; and a region where the S value is smaller than 0.3 V/decade.

Abstract: A semiconductor device with favorable electrical characteristics is provided. A semiconductor device with stable electrical characteristics is provided. The semiconductor device includes a first insulating layer, a second insulating layer, a third insulating layer, a fourth insulating layer, a semiconductor layer, and a first conductive layer. The second insulating layer is positioned over the first insulating layer and the island-shaped semiconductor layer is positioned over the second insulating layer. The second insulating layer has an island shape having an end portion outside a region overlapping with the semiconductor layer. The fourth insulating layer covers the second insulating layer, the semiconductor layer, the third insulating layer, and the first conductive layer, is in contact with part of a top surface of the semiconductor layer, and is in contact with the first insulating layer outside the end portion of the second insulating layer.

Abstract: To improve field-effect mobility and reliability of a transistor including an oxide semiconductor film. Provided is a semiconductor device including an oxide semiconductor film. The semiconductor device includes a first insulating film, the oxide semiconductor film over the first insulating film, a second insulating film and a third insulating film over the oxide semiconductor film, and a gate electrode over the second insulating film. The oxide semiconductor film includes a first oxide semiconductor film, a second oxide semiconductor film over the first oxide semiconductor film, and a third oxide semiconductor film over the second oxide semiconductor film. The first to third oxide semiconductor films contain the same element. The second oxide semiconductor film includes a region where the crystallinity is lower than the crystallinity of one or both of the first oxide semiconductor film and the third oxide semiconductor film.

Abstract: To reduce defects in an oxide semiconductor film in a semiconductor device. To improve the electrical characteristics and the reliability of a semiconductor device including an oxide semiconductor film. In a semiconductor device including a transistor including a gate electrode formed over a substrate, a gate insulating film covering the gate electrode, a multilayer film overlapping with the gate electrode with the gate insulating film provided therebetween, and a pair of electrodes in contact with the multilayer film, a first oxide insulating film covering the transistor, and a second oxide insulating film formed over the first oxide insulating film, the multilayer film includes an oxide semiconductor film and an oxide film containing In or Ga, the first oxide insulating film is an oxide insulating film through which oxygen is permeated, and the second oxide insulating film is an oxide insulating film containing more oxygen than that in the stoichiometric composition.

Abstract: To suppress a change in electrical characteristics and to improve reliability in a semiconductor device using a transistor including an oxide semiconductor. The semiconductor device includes a gate electrode over an insulating surface, an oxide semiconductor film overlapping with the gate electrode, a gate insulating film which is between the gate electrode and the oxide semiconductor film and is in contact with a surface of the oxide semiconductor film, a protective film in contact with an opposite surface of the surface of the oxide semiconductor film, and a pair of electrodes in contact with the oxide semiconductor film. In the gate insulating film or the protective film, the amount of gas having a mass-to-charge ratio m/z of 17 released by heat treatment is greater than the amount of nitrogen oxide released by heat treatment.

Abstract: A semiconductor device including an oxide semiconductor in which on-state current is high is provided. The semiconductor device includes a first transistor provided in a driver circuit portion and a second transistor provided in a pixel portion; the first transistor and the second transistor have different structures. Furthermore, the first transistor and the second transistor are transistors having a top-gate structure. In an oxide semiconductor film of each of the transistors, an impurity element is contained in regions which do not overlap with a gate electrode. The regions of the oxide semiconductor film which contain the impurity element function as low-resistance regions. Furthermore, the regions of the oxide semiconductor film which contain the impurity element are in contact with a film containing hydrogen. The first transistor provided in the driver circuit portion includes two gate electrodes between which the oxide semiconductor film is provided.