Abstract: To offer a semiconductor device including a thin film transistor having excellent characteristics and high reliability and a method for manufacturing the semiconductor device without variation. The summary is to include an inverted-staggered (bottom-gate structure) thin film transistor in which an oxide semiconductor film containing In, Ga, and Zn is used for a semiconductor layer and a buffer layer is provided between the semiconductor layer and source and drain electrode layers. An ohmic contact is formed by intentionally providing a buffer layer containing In, Ga, and Zn and having a higher carrier concentration than the semiconductor layer between the semiconductor layer and the source and drain electrode layers.

Abstract: A display device includes a pixel portion in which a pixel electrode layer is arranged in a matrix, and an inverted staggered thin film transistor having a combination of at least two kinds of oxide semiconductor layers with different amounts of oxygen is provided corresponding to the pixel electrode layer. In the periphery of the pixel portion in this display device, a pad portion is provided to be electrically connected to a common electrode layer formed on a counter substrate through a conductive layer made of the same material as the pixel electrode layer. One objection of our invention to prevent a defect due to separation of a thin film in various kinds of display devices is realized, by providing a structure suitable for a pad portion provided in a display panel.

Abstract: A protective circuit includes a non-linear element which includes a gate electrode, a gate insulating layer covering the gate electrode, a first oxide semiconductor layer overlapping with the gate electrode over the gate insulating layer, and a first wiring layer and a second wiring layer whose end portions overlap with the gate electrode over the first oxide semiconductor layer and in which a conductive layer and a second oxide semiconductor layer are stacked. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be reduced and the characteristics of the non-linear element can be improved.

Abstract: A novel display device and the like are provided. The data processing device includes a display panel, a means to obtain locational data, an arithmetic device, an angular sensor, a first housing, a second housing, and a hinge connected the first and second housings. The display panel is flexible, and is held in the inside of the first and second housings. The arithmetic device has a function of generating first image data based on locational data. The angular sensor supplies data of the folding angle between the housings to the arithmetic device. The arithmetic device has a function of generating second image data based on the locational data and the angular data. The second image data includes a second image and display coordinates of the second image. The display panel has a function of displaying an image based on the first image data and the second image data.

Abstract: An object is to provide a display device with excellent display characteristics, where a pixel circuit and a driver circuit provided over one substrate are formed using transistors which have different structures corresponding to characteristics of the respective circuits. The driver circuit portion includes a driver circuit transistor in which a gate electrode layer, a source electrode layer, and a drain electrode layer are formed using a metal film, and a channel layer is formed using an oxide semiconductor. The pixel portion includes a pixel transistor in which a gate electrode layer, a source electrode layer, and a drain electrode layer are formed using an oxide conductor, and a semiconductor layer is formed using an oxide semiconductor. The pixel transistor is formed using a light-transmitting material, and thus, a display device with higher aperture ratio can be manufactured.

Abstract: An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Abstract: An object is to provide favorable interface characteristics of a thin film transistor including an oxide semiconductor layer without mixing of an impurity such as moisture. Another object is to provide a semiconductor device including a thin film transistor having excellent electric characteristics and high reliability, and a method by which a semiconductor device can be manufactured with high productivity. A main point is to perform oxygen radical treatment on a surface of a gate insulating layer. Accordingly, there is a peak of the oxygen concentration at an interface between the gate insulating layer and a semiconductor layer, and the oxygen concentration of the gate insulating layer has a concentration gradient. The oxygen concentration is increased toward the interface between the gate insulating layer and the semiconductor layer.

Abstract: It is an object to provide a highly reliable semiconductor device with good electrical characteristics and a display device including the semiconductor device as a switching element. In a transistor including an oxide semiconductor layer, a needle crystal group provided on at least one surface side of the oxide semiconductor layer grows in a c-axis direction perpendicular to the surface and includes an a-b plane parallel to the surface, and a portion except for the needle crystal group is an amorphous region or a region in which amorphousness and microcrystals are mixed. Accordingly, a highly reliable semiconductor device with good electrical characteristics can be formed.

Abstract: A structure by which electric-field concentration which might occur between a source electrode and a drain electrode in a bottom-gate thin film transistor is relaxed and deterioration of the switching characteristics is suppressed, and a manufacturing method thereof. A bottom-gate thin film transistor in which an oxide semiconductor layer is provided over a source and drain electrodes is manufactured, and angle ?1 of the side surface of the source electrode which is in contact with the oxide semiconductor layer and angle ?2 of the side surface of the drain electrode which is in contact with the oxide semiconductor layer are each set to be greater than or equal to 20° and less than 90°, so that the distance from the top edge to the bottom edge in the side surface of each electrode is increased.

Abstract: It is an object to provide an oxide semiconductor which is suitable for use in a semiconductor device. Alternatively, it is another object to provide a semiconductor device using the oxide semiconductor. Provided is a semiconductor device including an In—Ga—Zn—O based oxide semiconductor layer in a channel formation region of a transistor. In the semiconductor device, the In—Ga—Zn—O based oxide semiconductor layer has a structure in which crystal grains represented by InGaO3(ZnO)m (m=1) are included in an amorphous structure represented by InGaO3(ZnO)m (m>0).

Abstract: An object is to improve field effect mobility of a thin film transistor using an oxide semiconductor. Another object is to suppress increase in off current even in a thin film transistor with improved field effect mobility. In a thin film transistor using an oxide semiconductor layer, by forming a semiconductor layer having higher electrical conductivity and a smaller thickness than the oxide semiconductor layer between the oxide semiconductor layer and a gate insulating layer, field effect mobility of the thin film transistor can be improved, and increase in off current can be suppressed.

Abstract: An object is to provide a display device with excellent display characteristics, where a pixel circuit and a driver circuit provided over one substrate are formed using transistors which have different structures corresponding to characteristics of the respective circuits. The driver circuit portion includes a driver circuit transistor in which a gate electrode layer, a source electrode layer, and a drain electrode layer are formed using a metal film, and a channel layer is formed using an oxide semiconductor. The pixel portion includes a pixel transistor in which a gate electrode layer, a source electrode layer, and a drain electrode layer are formed using an oxide conductor, and a semiconductor layer is formed using an oxide semiconductor. The pixel transistor is formed using a light-transmitting material, and thus, a display device with higher aperture ratio can be manufactured.

Abstract: A display device including an oxide semiconductor, a protective circuit and the like having appropriate structures and a small occupied area is necessary. The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first oxide semiconductor layer which is over the gate insulating layer and overlaps with the gate electrode; and a first wiring layer and a second wiring layer each of which is formed by stacking a conductive layer and a second oxide semiconductor layer and whose end portions are over the first oxide semiconductor layer and overlap with the gate electrode. The gate electrode of the non-linear element is connected to a scan line or a signal line, the first wiring layer or the second wiring layer of the non-linear element is directly connected to the gate electrode layer so as to apply potential of the gate electrode.

Abstract: To provide a semiconductor device including a thin film transistor having excellent electric characteristics and high reliability and a manufacturing method of the semiconductor device with high mass productivity. The summary is that an inverted-staggered (bottom-gate) thin film transistor is included in which an oxide semiconductor film containing In, Ga, and Zn is used as a semiconductor layer, a channel protective layer is provided in a region that overlaps a channel formation region of the semiconductor layer, and a buffer layer is provided between the semiconductor layer and source and drain electrodes. An ohmic contact is formed by intentionally providing the buffer layer having a higher carrier concentration than the semiconductor layer between the semiconductor layer and the source and drain electrodes.

Abstract: A protective circuit includes a non-linear element, which includes a gate electrode, a gate insulating layer covering the gate electrode, a pair of first and second wiring layers whose end portions overlap with the gate electrode over the gate insulating layer and in which a second oxide semiconductor layer and a conductive layer are stacked, and a first oxide semiconductor layer which overlaps with at least the gate electrode and which is in contact with the gate insulating layer, side face portions and part of top face portions of the conductive layer and side face portions of the second oxide semiconductor layer in the first wiring layer and the second wiring layer. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be decreased and the characteristics of the non-linear element can be improved.

Abstract: An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Abstract: An embodiment is to include an inverted staggered (bottom gate structure) thin film transistor in which an oxide semiconductor film containing In, Ga, and Zn is used as a semiconductor layer and a buffer layer is provided between the semiconductor layer and a source and drain electrode layers. The buffer layer having higher carrier concentration than the semiconductor layer is provided intentionally between the source and drain electrode layers and the semiconductor layer, whereby an ohmic contact is formed.

Abstract: An object is to improve field effect mobility of a thin film transistor using an oxide semiconductor. Another object is to suppress increase in off current even in a thin film transistor with improved field effect mobility. In a thin film transistor using an oxide semiconductor layer, by forming a semiconductor layer having higher electrical conductivity and a smaller thickness than the oxide semiconductor layer between the oxide semiconductor layer and a gate insulating layer, field effect mobility of the thin film transistor can be improved, and increase in off current can be suppressed.

Abstract: In order to take advantage of the properties of a display device including an oxide semiconductor, a protective circuit and the like having appropriate structures and a small occupied area are necessary. The protective circuit is formed using a non-linear element which includes a gate insulating film covering a gate electrode; a first oxide semiconductor layer over the gate insulating film; a channel protective layer covering a region which overlaps with a channel formation region of the first oxide semiconductor layer; and a first wiring layer and a second wiring layer each of which is formed by stacking a conductive layer and a second oxide semiconductor layer and over the first oxide semiconductor layer. The gate electrode is connected to a scan line or a signal line, the first wiring layer or the second wiring layer is directly connected to the gate electrode.

Abstract: An object is to provide favorable interface characteristics of a thin film transistor including an oxide semiconductor layer without mixing of an impurity such as moisture. Another object is to provide a semiconductor device including a thin film transistor having excellent electric characteristics and high reliability, and a method by which a semiconductor device can be manufactured with high productivity. A main point is to perform oxygen radical treatment on a surface of a gate insulating layer. Accordingly, there is a peak of the oxygen concentration at an interface between the gate insulating layer and a semiconductor layer, and the oxygen concentration of the gate insulating layer has a concentration gradient. The oxygen concentration is increased toward the interface between the gate insulating layer and the semiconductor layer.