Abstract: A display device includes a liquid crystal element, a transistor, a scan line, and a signal line. The liquid crystal element includes a pixel electrode, a liquid crystal layer, and a common electrode. The scan line and the signal line are each electrically connected to the transistor. The scan line and the signal line each include a metal layer. The transistor is electrically connected to the pixel electrode. A semiconductor layer of the transistor includes a stack of a first metal oxide layer and a second metal oxide layer. The first metal oxide layer includes a region with lower crystallinity than the second metal oxide layer. The transistor includes a first region connected to the pixel electrode. The pixel electrode, the common electrode, and the first region are each configured to transmit visible light. Visible light passes through the first region and the liquid crystal element and exits from the display device.

Abstract: A semiconductor device including an oxide semiconductor film that includes a transistor with excellent electrical characteristics is provided. It is a semiconductor device including a transistor. The transistor includes a gate electrode, a first insulating film, an oxide semiconductor film, a source electrode, a drain electrode, and a second insulating film. The source electrode and the drain electrode each include a first conductive film, a second conductive film over and in contact with the first conductive film, and a third conductive film over and in contact with the second conductive film. The second conductive film contains copper, the first conductive film and the third conductive film include a material that inhibits diffusion of copper, and an end portion of the second conductive film includes a region containing copper and silicon.

Abstract: To provide a novel method for manufacturing a semiconductor device. To provide a method for manufacturing a highly reliable semiconductor device at relatively low temperature. The method includes a first step of forming a first oxide semiconductor film in a deposition chamber and a second step of forming a second oxide semiconductor film over the first oxide semiconductor film in the deposition chamber. Water vapor partial pressure in an atmosphere in the deposition chamber is lower than water vapor partial pressure in atmospheric air. The first oxide semiconductor film and the second oxide semiconductor film are formed such that the first oxide semiconductor film and the second oxide semiconductor film each have crystallinity. The second oxide semiconductor film is formed such that the crystallinity of the second oxide semiconductor film is higher than the crystallinity of the first oxide semiconductor film.

Abstract: A semiconductor device with favorable electrical characteristics, a semiconductor device with stable electrical characteristics, or a highly reliable semiconductor device or display device is provided. A first insulating layer and a first conductive layer are stacked over a first region of a first metal oxide layer. A first layer is formed in contact with a second metal oxide layer and a second region of the first metal oxide layer that is not overlapped by the first insulating layer. Heat treatment is performed to lower the resistance of the second region and the second metal oxide layer. A second insulating layer is formed. A second conductive layer electrically connected to the second region is formed over the second insulating layer. Here, the first layer is formed to contain at least one of aluminum, titanium, tantalum, and tungsten.

Abstract: The field-effect mobility and reliability of a transistor including an oxide semiconductor film are improved. One embodiment of the present invention is a semiconductor device which includes a gate electrode, an insulating film over the gate electrode, an oxide semiconductor film over the insulating film, and a pair of electrodes over the oxide semiconductor 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 oxide semiconductor film, the second oxide semiconductor film, and the third oxide semiconductor film include the same element. The second oxide semiconductor film includes a region having lower crystallinity than one or both of the first oxide semiconductor film and the third oxide semiconductor film.

Abstract: The stability of steps of processing a wiring formed using copper or the like is increased. The concentration of impurities in a semiconductor film is reduced. Electrical characteristics of a semiconductor device are improved. A semiconductor device includes a semiconductor film, a pair of first protective films in contact with the semiconductor film, a pair of conductive films containing copper or the like in contact with the pair of first protective films, a pair of second protective films in contact with the pair of conductive films on the side opposite the pair of first protective films, a gate insulating film in contact with the semiconductor film, and a gate electrode overlapping with the semiconductor film with the gate insulating film therebetween. In a cross section, side surfaces of the pair of second protective films are located on the outer side of side surfaces of the pair of conductive films.

Abstract: To improve field-effect mobility and reliability of a transistor including an oxide semiconductor film. A semiconductor device includes an oxide semiconductor film, a gate electrode, an insulating film over the gate electrode, the oxide semiconductor film over the insulating film, and a pair of electrodes over the oxide semiconductor film. The oxide semiconductor film includes a first oxide semiconductor film and a second oxide semiconductor film over the first oxide semiconductor film. The first oxide semiconductor film and the second oxide semiconductor film, include the same element. The first oxide semiconductor film includes a region having lower crystallinity than the second oxide semiconductor film.

Abstract: The transistor includes a first gate electrode, a first insulating film over the first gate electrode, an oxide semiconductor film over the first insulating film, a source electrode over the oxide semiconductor film, a drain electrode over the oxide semiconductor film, a second insulating film over the oxide semiconductor film, the source electrode, and the drain electrode, and a second gate electrode over the second insulating film. The first insulating film includes a first opening. A connection electrode electrically connected to the first gate electrode through the first opening is formed over the first insulating film. The second insulating film includes a second opening that reaches the connection electrode. The second gate electrode includes an oxide conductive film and a metal film over the oxide conductive film. The connection electrode and the second gate electrode are electrically connected to each other through the metal film.

Abstract: To provide a novel method for manufacturing a semiconductor device. To provide a method for manufacturing a highly reliable semiconductor device at relatively low temperature. The method includes a first step of forming a first oxide semiconductor film in a deposition chamber and a second step of forming a second oxide semiconductor film over the first oxide semiconductor film in the deposition chamber. Water vapor partial pressure in an atmosphere in the deposition chamber is lower than water vapor partial pressure in atmospheric air. The first oxide semiconductor film and the second oxide semiconductor film are formed such that the first oxide semiconductor film and the second oxide semiconductor film each have crystallinity. The second oxide semiconductor film is formed such that the crystallinity of the second oxide semiconductor film is higher than the crystallinity of the first oxide semiconductor film.

Abstract: The stability of steps of processing a wiring formed using copper or the like is increased. The concentration of impurities in a semiconductor film is reduced. Electrical characteristics of a semiconductor device are improved. A semiconductor device includes a semiconductor film, a pair of first protective films in contact with the semiconductor film, a pair of conductive films containing copper or the like in contact with the pair of first protective films, a pair of second protective films in contact with the pair of conductive films on the side opposite the pair of first protective films, a gate insulating film in contact with the semiconductor film, and a gate electrode overlapping with the semiconductor film with the gate insulating film therebetween. In a cross section, side surfaces of the pair of second protective films are located on the outer side of side surfaces of the pair of conductive films.

Abstract: The transistor includes a first gate electrode, a first insulating film over the first gate electrode, an oxide semiconductor film over the first insulating film, a source electrode over the oxide semiconductor film, a drain electrode over the oxide semiconductor film, a second insulating film over the oxide semiconductor film, the source electrode, and the drain electrode, and a second gate electrode over the second insulating film. The first insulating film includes a first opening. A connection electrode electrically connected to the first gate electrode through the first opening is formed over the first insulating film. The second insulating film includes a second opening that reaches the connection electrode. The second gate electrode includes an oxide conductive film and a metal film over the oxide conductive film. The connection electrode and the second gate electrode are electrically connected to each other through the metal film.

Abstract: To provide a semiconductor device including a transistor in which an oxide semiconductor is used and on-state current is high. In a semiconductor device including 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 which conductive films serving as a gate electrode, a source electrode, and a drain electrode do not overlap. Furthermore, in an oxide semiconductor film, an impurity element is contained in a region which does not overlap with the gate electrode, the source electrode, and the drain electrode.

Abstract: A semiconductor device which has favorable electrical characteristics is provided. A method for manufacturing a semiconductor device with high productivity is provided. A method for manufacturing a semiconductor device with a high yield is provided.

Abstract: In a transistor including an oxide semiconductor film, field-effect mobility and reliability are improved. A semiconductor device includes a gate electrode, an insulating film over the gate electrode, an oxide semiconductor film over the insulating film, and a pair of electrodes over the oxide semiconductor film. The oxide semiconductor film includes a first oxide semiconductor film and a second oxide semiconductor film over the first oxide semiconductor film. The first oxide semiconductor film is formed using In oxide or In—Zn oxide. The second oxide semiconductor film is formed using In-M-Zn oxide (M is Al, Ga, or Y) and includes a region where the number of In atoms is 40% or more and 50% or less and the number of M atoms is 5% or more and 30% or less of the total number of In, M, and Zn atoms.

Abstract: The field-effect mobility and reliability of a transistor including an oxide semiconductor film are improved. A semiconductor layer of a transistor is formed using a composite oxide semiconductor in which a first region and a second region are mixed. The first region includes a plurality of first clusters containing one or more of indium, zinc, and oxygen as a main component. The second region includes a plurality of second clusters containing one or more of indium, an element M (M represents Al, Ga, Y, or Sn), zinc, and oxygen. The first region includes a portion in which the plurality of first clusters are connected to each other. The second region includes a portion in which the plurality of second clusters are connected to each other.

Abstract: A transistor includes a multilayer film in which an oxide semiconductor film and an oxide film are stacked, a gate electrode, and a gate insulating film. The multilayer film overlaps with the gate electrode with the gate insulating film interposed therebetween. The multilayer film has a shape having a first angle between a bottom surface of the oxide semiconductor film and a side surface of the oxide semiconductor film and a second angle between a bottom surface of the oxide film and a side surface of the oxide film. The first angle is acute and smaller than the second angle. Further, a semiconductor device including such a transistor is manufactured.

Abstract: The stability of a step of processing a wiring formed using copper, aluminum, gold, silver, molybdenum, or the like is increased. Moreover, the concentration of impurities in a semiconductor film is reduced. Moreover, the electrical characteristics of a semiconductor device are improved. In a transistor including an oxide semiconductor film, an oxide film in contact with the oxide semiconductor film, and a pair of conductive films being in contact with the oxide film and including copper, aluminum, gold, silver, molybdenum, or the like, the oxide film has a plurality of crystal parts and has c-axis alignment in the crystal parts, and the c-axes are aligned in a direction parallel to a normal vector of a top surface of the oxide semiconductor film or the oxide film.

Abstract: The field-effect mobility and reliability of a transistor including an oxide semiconductor film are improved. A semiconductor layer of a transistor is formed using a composite oxide semiconductor in which a first region and a second region are mixed. The first region includes a plurality of first clusters containing one or more of indium, zinc, and oxygen as a main component. The second region includes a plurality of second clusters containing one or more of indium, an element M (M represents Al, Ga, Y, or Sn), zinc, and oxygen. The first region includes a portion in which the plurality of first clusters are connected to each other. The second region includes a portion in which the plurality of second clusters are connected to each other.

Abstract: A transistor includes a multilayer film in which an oxide semiconductor film and an oxide film are stacked, a gate electrode, and a gate insulating film. The multilayer film overlaps with the gate electrode with the gate insulating film interposed therebetween. The multilayer film has a shape having a first angle between a bottom surface of the oxide semiconductor film and a side surface of the oxide semiconductor film and a second angle between a bottom surface of the oxide film and a side surface of the oxide film. The first angle is acute and smaller than the second angle. Further, a semiconductor device including such a transistor is manufactured.

Abstract: The stability of a step of processing a wiring formed using copper, aluminum, gold, silver, molybdenum, or the like is increased. Moreover, the concentration of impurities in a semiconductor film is reduced. Moreover, the electrical characteristics of a semiconductor device are improved. In a transistor including an oxide semiconductor film, an oxide film in contact with the oxide semiconductor film, and a pair of conductive films being in contact with the oxide film and including copper, aluminum, gold, silver, molybdenum, or the like, the oxide film has a plurality of crystal parts and has c-axis alignment in the crystal parts, and the c-axes are aligned in a direction parallel to a normal vector of a top surface of the oxide semiconductor film or the oxide film.