An embodiment is a semiconductor device which includes a first oxide semiconductor layer over a substrate having an insulating surface and including a crystalline region formed by growth from a surface of the first oxide semiconductor layer toward an inside; a second oxide semiconductor layer over the first oxide semiconductor layer; a source electrode layer and a drain electrode layer which are in contact with the second oxide semiconductor layer; a gate insulating layer covering the second oxide semiconductor layer, the source electrode layer, and the drain electrode layer; and a gate electrode layer over the gate insulating layer and in a region overlapping with the second oxide semiconductor layer. The second oxide semiconductor layer is a layer including a crystal formed by growth from the crystalline region.

A mist-CVD apparatus contains a first atomizer for atomizing a first metal oxide precursor and generating a first mist of the first metal oxide precursor; a second atomizer for atomizing a second metal oxide precursor and generating a second mist of the second metal oxide precursor; a carrier-gas supplier for supplying a carrier gas to convey the first and second mists; a film-forming unit for forming a film on a substrate by subjecting the first and second mists to a thermal reaction; and a first conveyance pipe through which the first mist and the carrier gas are conveyed to the film forming chamber, a second conveyance pipe through which the second mist and the carrier gas are conveyed to the film forming chamber.

A laminate contains a crystal substrate; a middle layer formed on a main surface of the crystal substrate, the middle layer comprising a mixture of an amorphous region in an amorphous phase and a crystal region in a crystal phase having a corundum structure mainly made of a first metal oxide; and a crystal layer formed on the middle layer and having a corundum structure mainly made of a second metal oxide, wherein the crystal region is an epitaxially grown layer from a crystal plane of the crystal substrate.

A novel material and a transistor including the novel material are provided. One embodiment of the present invention is a composite oxide including at least two regions. One of the regions includes In, Zn and an element M1 (the element M1 is one or more of Al, Ga, Si, B, Y, Ti, Fe, Ni, Ge, Zr, Mo, La, Ce, Nd, Hf, Ta, W, Mg, V, Be, and Cu) and the other of the regions includes In, Zn, and an element M2 (the element M2 is one or more of Al, Ga, Si, B, Y, Ti, Fe, Ni, Ge, Zr, Mo, La, Ce, Nd, Hf, Ta, W, Mg, V, Be, and Cu). In an analysis of the composite oxide by energy dispersive X-ray spectroscopy, the detected concentration of the element M1 in a first region is less than the detected concentration of the element M2 in a second region, and a surrounding portion of the first region is unclear in an observed mapping image of the energy dispersive X-ray spectroscopy.

A novel material and a transistor including the novel material are provided. One embodiment of the present invention is a composite oxide including at least two regions. One of the regions includes In, Zn and an element M1 (the element M1 is one or more of Al, Ga, Si, B, Y, Ti, Fe, Ni, Ge, Zr, Mo, La, Ce, Nd, Hf, Ta, W, Mg, V, Be, and Cu) and the other of the regions includes In, Zn, and an element M2 (the element M2 is one or more of Al, Ga, Si, B, Y, Ti, Fe, Ni, Ge, Zr, Mo, La, Ce, Nd, Hf, Ta, W, Mg, V, Be, and Cu). In an analysis of the composite oxide by energy dispersive X-ray spectroscopy, the detected concentration of the element M1 in a first region is less than the detected concentration of the element M2 in a second region, and a surrounding portion of the first region is unclear in an observed mapping image of the energy dispersive X-ray spectroscopy.

An electronic device comprises a panel, a driving circuit configured to drive the panel, and a transistor disposed in the panel. The transistor includes a first insulation film on a substrate, an active layer disposed on the first insulation film, a second insulation film disposed on the active layer and the first insulation film to cover the active layer, the second insulation film having a thickness smaller than a thickness of the first insulation film, a source electrode disposed on the second insulation film and spaced apart from the active layer by the second insulation film, the source electrode overlapping an end of the active layer, and a drain electrode disposed on the second insulation film and spaced apart from the active layer by the second insulation film, the drain electrode overlapping another end of the active layer.

A semiconductor device having favorable electric characteristics and a manufacturing method thereof are provided. A transistor includes an oxide semiconductor layer formed over an insulating layer, a source electrode layer and a drain electrode layer which overlap with part of the oxide semiconductor layer, a gate insulating layer in contact with part of the oxide semiconductor layer, and a gate electrode layer over the gate insulating layer. In the transistor, a buffer layer having n-type conductivity is formed between the source electrode layer and the oxide semiconductor layer and between the drain electrode layer and the oxide semiconductor layer. Thus, parasitic resistance is reduced, resulting in improvement of on-state characteristics of the transistor.

An electronic device including a two-dimensional electron gas is provided. The electronic device includes a substrate, a first material layer disposed on the substrate and formed of a binary oxide, a second material layer disposed on the first material layer and formed of a binary oxide, and a two-dimensional electron gas generated between the first material layer and the second material layer.

A semiconductor device with a structure in which an increase in the number of oxygen vacancies in an oxide semiconductor layer can be suppressed and a method for manufacturing the semiconductor device are provided. The semiconductor device includes an oxide insulating layer; intermediate layers apart from each other over the oxide insulating layer; a source electrode layer and a drain electrode layer over the intermediate layers; an oxide semiconductor layer that is electrically connected to the source electrode layer and the drain electrode layer and is in contact with the oxide insulating layer; a gate insulating film over the source electrode layer, the drain electrode layer, and the oxide semiconductor layer; and a gate electrode layer that is over the gate insulating film and overlaps with the source electrode layer, the drain electrode layer, and the oxide semiconductor layer.

The film structure according to an embodiment of the present invention includes at least one active monolayer having an energy level quantized in at least one axial direction and at least one barrier alternately stacked with the at least one active monolayer. Current flows through the active monolayer, and the current flow may be limited by the quantized energy level.