A semiconductor device or the like capable of preventing malfunction of a driver circuit is provided. In a driver circuit for driving a power device used for current supply, a transistor including an oxide semiconductor is used as a transistor in a circuit (specifically, for example, a level shift circuit) requiring a high withstand voltage. In addition, a transistor (for example, a silicon transistor or the like) capable of higher operation than a transistor including an oxide semiconductor is preferably used as a transistor in a circuit (specifically, for example, a buffer circuit, a flip-flop circuit, or the like) requiring a lower withstand voltage than the level shift circuit.

A semiconductor device includes an oxide semiconductor layer including a crystalline region over an insulating surface, a source electrode layer and a drain electrode layer in contact with the oxide semiconductor layer, a gate insulating layer covering the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode layer over the gate insulating layer in a region overlapping with the crystalline region. The crystalline region includes a crystal whose c-axis is aligned in a direction substantially perpendicular to a surface of the oxide semiconductor layer.

An object is to stabilize electric characteristics of a semiconductor device including an oxide semiconductor to increase reliability. The semiconductor device includes an insulating film; a first metal oxide film on and in contact with the insulating film; an oxide semiconductor film partly in contact with the first metal oxide film; source and drain electrodes electrically connected to the oxide semiconductor film; a second metal oxide film partly in contact with the oxide semiconductor film; a gate insulating film on and in contact with the second metal oxide film; and a gate electrode over the gate insulating film.

Oxide layers which contain at least one metal element that is the same as that contained in an oxide semiconductor layer including a channel are formed in contact with the top surface and the bottom surface of the oxide semiconductor layer, whereby an interface state is not likely to be generated at each of an upper interface and a lower interface of the oxide semiconductor layer. Further, it is preferable that an oxide layer, which is formed using a material and a method similar to those of the oxide layers be formed over the oxide layers Accordingly, the interface state hardly influences the movement of electrons.

To provide a semiconductor device which has transistor characteristics with little variation and includes an oxide semiconductor. The semiconductor device includes an insulating film over a conductive film and an oxide semiconductor film over the insulating film. The oxide semiconductor film includes a first oxide semiconductor layer, a second oxide semiconductor layer over the first oxide semiconductor layer, and a third oxide semiconductor layer over the second oxide semiconductor layer. The energy level of a bottom of a conduction band of the second oxide semiconductor layer is lower than those of the first and third oxide semiconductor layers. An end portion of the second oxide semiconductor layer is positioned on an inner side than an end portion of the first oxide semiconductor layer.

An object is to obtain a semiconductor device having a high sensitivity in detecting signals and a wide dynamic range, using a thin film transistor in which an oxide semiconductor layer is used. An analog circuit is formed with the use of a thin film transistor including an oxide semiconductor which has a function as a channel formation layer, has a hydrogen concentration of 510.sup.19 atoms/cm.sup.3 or lower, and substantially functions as an insulator in the state where no electric field is generated. Thus, a semiconductor device having a high sensitivity in detecting signals and a wide dynamic range can be obtained.

A semiconductor device includes an extremely thin semiconductor-on-insulator substrate (ETSOI) having a base substrate, a thin semiconductor layer and a buried dielectric therebetween. A device channel is formed in the thin semiconductor layer. Source and drain regions are formed at opposing positions relative to the device channel. The source and drain regions include an n-type material deposited on the buried dielectric within a thickness of the thin semiconductor layer. A gate structure is formed over the device channel.

An oxide semiconductor film which has more stable electric conductivity is provided. The oxide semiconductor film comprises a crystalline region. The oxide semiconductor film has a first peak of electron diffraction intensity with a full width at half maximum of greater than or equal to 0.4 nm.sup.1 and less than or equal to 0.7 nm.sup.1 in a region where a magnitude of a scattering vector is greater than or equal to 3.3 nm.sup.1 and less than or equal to 4.1 nm.sup.1. The oxide semiconductor film has a second peak of electron diffraction intensity with a full width at half maximum of greater than or equal to 0.45 nm.sup.1 and less than or equal to 1.4 nm.sup.1 in a region where a magnitude of a scattering vector is greater than or equal to 5.5 nm.sup.1 and less than or equal to 7.1 nm.sup.1.

Provided are a transistor which has electrical characteristics requisite for its purpose and uses an oxide semiconductor layer and a semiconductor device including the transistor. In the bottom-gate transistor in which at least a gate electrode layer, a gate insulating film, and the semiconductor layer are stacked in this order, an oxide semiconductor stacked layer including at least two oxide semiconductor layers whose energy gaps are different from each other is used as the semiconductor layer. Oxygen and/or a dopant may be added to the oxide semiconductor stacked layer.

Manufacturing method including forming, over substrate, TFT layer, planarization layer, and display element in this order. Forming of TFT layer involves forming passivation layer to cover TFT layer electrode, such as upper electrode, and to come in contact with planarizing layer. Forming of display element involves forming bottom electrode to come in contact with planarizing layer. TFT layer electrode and bottom electrode are connected by: first forming, in planarizing layer, first contact hole exposing passivation layer at bottom thereof; then forming second contact hole exposing TFT layer electrode at bottom thereof through dry-etching passivation layer exposed at bottom of first contact hole using fluorine-containing gas; then forming liquid repellent film containing fluorine on passivation layer inner surface facing second contact hole; and forming bottom electrode along planarizing layer inner surface and passivation layer inner surface respectively facing first contact hole and second contact hole.