Abstract: A method for manufacturing an SOI substrate in which crystal defects of a single crystal semiconductor layer are reduced even if a single crystal semiconductor substrate including crystal defects is used. A first oxide film is formed on a single crystal semiconductor substrate; the first oxide film is removed; a surface of the single crystal semiconductor substrate from which the first oxide film is removed is irradiated with laser light; a second oxide film is formed on the single crystal semiconductor substrate; an embrittled region is formed in the single crystal semiconductor substrate by irradiating the single crystal semiconductor substrate with ions through the second oxide film; bonding the second oxide film and the semiconductor substrate so as to face each other; and the single crystal semiconductor substrate is separated at the embrittled region by heat treatment to obtain a single crystal semiconductor layer bonded to the semiconductor substrate.

Abstract: An object is to provide a semiconductor device including an oxide semiconductor in which miniaturization is achieved while favorable characteristics are maintained. The semiconductor includes an oxide semiconductor layer, a source electrode and a drain electrode in contact with the oxide semiconductor layer, a gate electrode overlapping with the oxide semiconductor layer, a gate insulating layer provided between the oxide semiconductor layer and the gate electrode, and an insulating layer provided in contact with the oxide semiconductor layer. A side surface of the oxide semiconductor layer is in contact with the source electrode or the drain electrode. An upper surface of the oxide semiconductor layer overlaps with the source electrode or the drain electrode with the insulating layer interposed between the oxide semiconductor layer and the source electrode or the drain electrode.

Abstract: It is an object to provide a method for manufacturing an SOI substrate in which crystal defects of a single crystal semiconductor layer are reduced even when a single crystal semiconductor substrate in which crystal defects exist is used. Such an SOI substrate can be manufactured through the steps of forming a single crystal semiconductor layer which has an extremely small number of defects over a single crystal semiconductor substrate by an epitaxial growth method; forming an oxide film on the single crystal semiconductor substrate by thermal oxidation treatment; introducing ions into the single crystal semiconductor substrate through the oxide film; bonding the single crystal semiconductor substrate into which the ions are introduced and a semiconductor substrate to each other; causing separation by heat treatment; and performing planarization treatment on the single crystal semiconductor layer provided over the semiconductor substrate.

Abstract: One object of the present invention is to increase an aperture ratio of a semiconductor device. A pixel portion and a driver circuit are provided over one substrate. The first thin film transistor (TFT) in the pixel portion includes: a gate electrode layer over the substrate; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; source and drain electrode layers over the oxide semiconductor layer; over the gate insulating layer, the oxide semiconductor layer, the source and drain electrode layers, a protective insulating layer which is in contact with part of the oxide semiconductor layer; and a pixel electrode layer over the protective insulating layer. The pixel portion has light-transmitting properties. Further, a material of source and drain electrode layers of a second TFT in the driver circuit is different from a material of those of the first TFT.

Abstract: To provide a novel display device where display quality does not deteriorate. The display device includes a display portion configured to display a still image at a frame frequency of 30 Hz or lower. The display portion includes a driver circuit, a plurality of wirings, and a pixel portion. The pixel portion comprises a plurality of pixels. Each of the plurality of pixels comprises a transistor, a display element, and a capacitor. A channel is formed in an oxide semiconductor layer included in the transistor. A gate of the transistor is electrically connected to one of the plurality of wirings. The driver circuit performs scanning where the plurality of wirings in one of odd-numbered rows and even-numbered rows are sequentially selected and scanning where the plurality of wirings in the other of the odd-numbered rows and the even-numbered rows are sequentially selected.

Abstract: An object is to provide a semiconductor device including an oxide semiconductor in which miniaturization is achieved while favorable characteristics are maintained. The semiconductor includes an oxide semiconductor layer, a source electrode and a drain electrode in contact with the oxide semiconductor layer, a gate electrode overlapping with the oxide semiconductor layer, a gate insulating layer provided between the oxide semiconductor layer and the gate electrode, and an insulating layer provided in contact with the oxide semiconductor layer. A side surface of the oxide semiconductor layer is in contact with the source electrode or the drain electrode. An upper surface of the oxide semiconductor layer overlaps with the source electrode or the drain electrode with the insulating layer interposed between the oxide semiconductor layer and the source electrode or the drain electrode.

Abstract: An object is to provide a semiconductor device including an oxide semiconductor in which miniaturization is achieved while favorable characteristics are maintained. The semiconductor includes an oxide semiconductor layer, a source electrode and a drain electrode in contact with the oxide semiconductor layer, a gate electrode overlapping with the oxide semiconductor layer, a gate insulating layer provided between the oxide semiconductor layer and the gate electrode, and an insulating layer provided in contact with the oxide semiconductor layer. A side surface of the oxide semiconductor layer is in contact with the source electrode or the drain electrode. An upper surface of the oxide semiconductor layer overlaps with the source electrode or the drain electrode with the insulating layer interposed between the oxide semiconductor layer and the source electrode or the drain electrode.

Abstract: An object is to provide an SOI substrate with excellent characteristics even in the case where a single crystal semiconductor substrate having crystal defects is used. Another object is to provide a semiconductor device using such an SOI substrate. A single crystal semiconductor layer is formed by an epitaxial growth method over a surface of a single crystal semiconductor substrate. The single crystal semiconductor layer is subjected to first thermal oxidation treatment to form a first oxide film. A surface of the first oxide film is irradiated with ions, whereby the ions are introduced to the single crystal semiconductor layer. The single crystal semiconductor layer and a base substrate are bonded with the first oxide film interposed therebetween. The single crystal semiconductor layer is divided at a region where the ions are introduced by performing thermal treatment, so that the single crystal semiconductor layer is partly left over the base substrate.

Abstract: A method for manufacturing an SOI substrate in which crystal defects of a single crystal semiconductor layer are reduced is provided. An oxide film containing halogen is formed on each of surfaces of a single crystal semiconductor substrate and of a semiconductor substrate provided with a single crystal semiconductor layer separated from the single crystal semiconductor substrate, whereby impurities that exist on the surfaces of and inside the substrates are decreased. In addition, the single crystal semiconductor layer provided over the semiconductor substrate is irradiated with a laser beam, whereby crystallinity of the single crystal semiconductor layer is improved and planarity is improved.

Abstract: An object is to provide a semiconductor device including an oxide semiconductor in which miniaturization is achieved while favorable characteristics are maintained. The semiconductor includes an oxide semiconductor layer, a source electrode and a drain electrode in contact with the oxide semiconductor layer, a gate electrode overlapping with the oxide semiconductor layer, a gate insulating layer provided between the oxide semiconductor layer and the gate electrode, and an insulating layer provided in contact with the oxide semiconductor layer. A side surface of the oxide semiconductor layer is in contact with the source electrode or the drain electrode. An upper surface of the oxide semiconductor layer overlaps with the source electrode or the drain electrode with the insulating layer interposed between the oxide semiconductor layer and the source electrode or the drain electrode.

Abstract: One object of the present invention is to increase an aperture ratio of a semiconductor device. A pixel portion and a driver circuit are provided over one substrate. The first thin film transistor (TFT) in the pixel portion includes: a gate electrode layer over the substrate; a gate insulating layer over the gate electrode layer; an oxide semiconductor layer over the gate insulating layer; source and drain electrode layers over the oxide semiconductor layer; over the gate insulating layer, the oxide semiconductor layer, the source and drain electrode layers, a protective insulating layer which is in contact with part of the oxide semiconductor layer; and a pixel electrode layer over the protective insulating layer. The pixel portion has light-transmitting properties. Further, a material of source and drain electrode layers of a second TFT in the driver circuit is different from a material of those of the first TFT.

Abstract: An object is to provide an SOI substrate with excellent characteristics even in the case where a single crystal semiconductor substrate having crystal defects is used. Another object is to provide a semiconductor device using such an SOI substrate. A single crystal semiconductor layer is formed by an epitaxial growth method over a surface of a single crystal semiconductor substrate. The single crystal semiconductor layer is subjected to first thermal oxidation treatment to form a first oxide film. A surface of the first oxide film is irradiated with ions, whereby the ions are introduced to the single crystal semiconductor layer. The single crystal semiconductor layer and a base substrate are bonded with the first oxide film interposed therebetween. The single crystal semiconductor layer is divided at a region where the ions are introduced by performing thermal treatment, so that the single crystal semiconductor layer is partly left over the base substrate.

Abstract: A method for manufacturing an SOI substrate in which crystal defects of a single crystal semiconductor layer are reduced is provided. An oxide film containing halogen is formed on each of surfaces of a single crystal semiconductor substrate and of a semiconductor substrate provided with a single crystal semiconductor layer separated from the single crystal semiconductor substrate, whereby impurities that exist on the surfaces of and inside the substrates are decreased. In addition, the single crystal semiconductor layer provided over the semiconductor substrate is irradiated with a laser beam, whereby crystallinity of the single crystal semiconductor layer is improved and planarity is improved.

Abstract: A method for manufacturing an SOI substrate in which crystal defects of a single crystal semiconductor layer are reduced even if a single crystal semiconductor substrate including crystal defects is used. A first oxide film is formed on a single crystal semiconductor substrate; the first oxide film is removed; a surface of the single crystal semiconductor substrate from which the first oxide film is removed is irradiated with laser light; a second oxide film is formed on the single crystal semiconductor substrate; an embrittled region is formed in the single crystal semiconductor substrate by irradiating the single crystal semiconductor substrate with ions through the second oxide film; bonding the second oxide film and the semiconductor substrate so as to face each other; and the single crystal semiconductor substrate is separated at the embrittled region by heat treatment to obtain a single crystal semiconductor layer bonded to the semiconductor substrate.

Abstract: It is an object to provide a method for manufacturing an SOI substrate in which crystal defects of a single crystal semiconductor layer are reduced even when a single crystal semiconductor substrate in which crystal defects exist is used. Such an SOI substrate can be manufactured through the steps of forming a single crystal semiconductor layer which has an extremely small number of defects over a single crystal semiconductor substrate by an epitaxial growth method; forming an oxide film on the single crystal semiconductor substrate by thermal oxidation treatment; introducing ions into the single crystal semiconductor substrate through the oxide film; bonding the single crystal semiconductor substrate into which the ions are introduced and a semiconductor substrate to each other; causing separation by heat treatment; and performing planarization treatment on the single crystal semiconductor layer provided over the semiconductor substrate.