Abstract: A highly reliable semiconductor device including a transistor using an oxide semiconductor is provided. In a semiconductor device including a bottom-gate transistor including an oxide semiconductor layer, a first insulating layer is formed in contact with the oxide semiconductor layer, and an oxygen doping treatment is performed thereon, whereby the first insulating layer is made to contain oxygen in excess of the stoichiometric composition. The formation of the second insulating layer over the first insulating layer enables excess oxygen included in the first insulating layer to be supplied efficiently to the oxide semiconductor layer. Accordingly, the highly reliable semiconductor device with stable electric characteristics can be provided.

Abstract: An object of one embodiment of the present invention is to provide a highly reliable semiconductor device by giving stable electric characteristics to a transistor including an oxide semiconductor film. The semiconductor device includes a gate electrode layer over a substrate, a gate insulating film over the gate electrode layer, an oxide semiconductor film over the gate insulating film, a drain electrode layer provided over the oxide semiconductor film to overlap with the gate electrode layer, and a source electrode layer provided to cover an outer edge portion of the oxide semiconductor film. The outer edge portion of the drain electrode layer is positioned on the inner side than the outer edge portion of the gate electrode layer.

Abstract: A highly reliable semiconductor device including a transistor using an oxide semiconductor is provided. In a semiconductor device including a bottom-gate transistor including an oxide semiconductor layer, a first insulating layer is formed in contact with the oxide semiconductor layer, and an oxygen doping treatment is performed thereon, whereby the first insulating layer is made to contain oxygen in excess of the stoichiometric composition. The formation of the second insulating layer over the first insulating layer enables excess oxygen included in the first insulating layer to be supplied efficiently to the oxide semiconductor layer. Accordingly, the highly reliable semiconductor device with stable electric characteristics can be provided.

Abstract: A highly reliable semiconductor device including a transistor using an oxide semiconductor is provided. In a semiconductor device including a bottom-gate transistor including an oxide semiconductor layer, a first insulating layer is formed in contact with the oxide semiconductor layer, and an oxygen doping treatment is performed thereon, whereby the first insulating layer is made to contain oxygen in excess of the stoichiometric composition. The formation of the second insulating layer over the first insulating layer enables excess oxygen included in the first insulating layer to be supplied efficiently to the oxide semiconductor layer. Accordingly, the highly reliable semiconductor device with stable electric characteristics can be provided.

Abstract: An object of one embodiment of the present invention is to provide a highly reliable semiconductor device by giving stable electric characteristics to a transistor including an oxide semiconductor film. The semiconductor device includes a gate electrode layer over a substrate, a gate insulating film over the gate electrode layer, an oxide semiconductor film over the gate insulating film, a drain electrode layer provided over the oxide semiconductor film to overlap with the gate electrode layer, and a source electrode layer provided to cover an outer edge portion of the oxide semiconductor film. The outer edge portion of the drain electrode layer is positioned on the inner side than the outer edge portion of the gate electrode layer.

Abstract: An object of one embodiment of the present invention is to provide a highly reliable semiconductor device by giving stable electric characteristics to a transistor including an oxide semiconductor film. The semiconductor device includes a gate electrode layer over a substrate, a gate insulating film over the gate electrode layer, an oxide semiconductor film over the gate insulating film, a drain electrode layer provided over the oxide semiconductor film to overlap with the gate electrode layer, and a source electrode layer provided to cover an outer edge portion of the oxide semiconductor film. The outer edge portion of the drain electrode layer is positioned on the inner side than the outer edge portion of the gate electrode layer.

Abstract: A highly reliable semiconductor device in which a transistor including an oxide semiconductor film has stable electric characteristics is manufactured. In the semiconductor device which includes an inverted-staggered transistor having a bottom-gate structure and being provided over a substrate having an insulating surface, at least a first gate insulating film and a second gate insulating film are provided between a gate electrode layer and an oxide semiconductor film, and heat treatment is performed at a temperature of 450° C. or higher, preferably 650° C. or higher, and then the oxide semiconductor film is formed. By the heat treatment at a temperature of 450° C. or higher before the formation of the oxide semiconductor film, diffusion of hydrogen elements into the oxide semiconductor film, which causes degradation or variations in electric characteristics of the transistor, can be reduced, so that the transistor can have stable electric characteristics.