Abstract: Provided is an oxide semiconductor film which has more stable electric characteristics and essentially consists of indium zinc oxide. In addition, provided is a highly reliable semiconductor device which has stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film essentially consisting of indium zinc oxide has a hexagonal crystal structure in which the a-b plane is substantially parallel to a surface of the oxide semiconductor film and a rhombohedral crystal structure in which the a-b plane is substantially parallel to the surface of the oxide semiconductor film.

Abstract: To suppress a change in electrical characteristics and to improve reliability in a semiconductor device using a transistor including an oxide semiconductor. The semiconductor device includes a gate electrode over an insulating surface, an oxide semiconductor film overlapping with the gate electrode, a gate insulating film which is between the gate electrode and the oxide semiconductor film and is in contact with a surface of the oxide semiconductor film, a protective film in contact with an opposite surface of the surface of the oxide semiconductor film, and a pair of electrodes in contact with the oxide semiconductor film. In the gate insulating film or the protective film, the amount of gas having a mass-to-charge ratio m/z of 17 released by heat treatment is greater than the amount of nitrogen oxide released by heat treatment.

Abstract: An object is, in a thin film transistor including an oxide semiconductor layer, to reduce contact resistance between the oxide semiconductor layer and source and drain electrode layers electrically connected to the oxide semiconductor layer. The source and drain electrode layers have a stacked-layer structure of two or more layers in which a layer in contact with the oxide semiconductor layer is formed using a metal whose work function is lower than the work function of the oxide semiconductor layer or an alloy containing such a metal. Layers other than the layer in contact with the oxide semiconductor layer of the source and drain electrode layers are formed using an element selected from Al, Cr, Cu, Ta, Ti, Mo, or W, an alloy containing any of these elements as a component, an alloy containing any of these elements in combination, or the like.

Abstract: Manufactured is a transistor including an oxide semiconductor layer, a source electrode layer and a drain electrode layer overlapping with part of the oxide semiconductor layer, a gate insulating layer overlapping with the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode overlapping with part of the oxide semiconductor layer with the gate insulating layer provided therebetween, wherein, after the oxide semiconductor layer which is to be a channel formation region is irradiated with light and the light irradiation is stopped, a relaxation time of carriers in photoresponse characteristics of the oxide semiconductor layer has at least two kinds of modes: ?1 and ?2, ?1<?2 is satisfied, and ?2 is 300 seconds or less. In addition, a semiconductor device including the transistor is manufactured.

Abstract: An object is to provide a semiconductor device including an oxide semiconductor, which has stable electrical characteristics and high reliability. In a manufacturing process of a bottom-gate transistor including an oxide semiconductor layer, heat treatment in an atmosphere containing oxygen and heat treatment in vacuum are sequentially performed for dehydration or dehydrogenation of the oxide semiconductor layer. In addition, irradiation with light having a short wavelength is performed concurrently with the heat treatment, whereby elimination of hydrogen, OH, or the like is promoted. A transistor including an oxide semiconductor layer on which dehydration or dehydrogenation treatment is performed through such heat treatment has improved stability, so that variation in electrical characteristics of the transistor due to light irradiation or a bias-temperature stress (BT) test is suppressed.

Abstract: Provided is an oxide semiconductor film which has more stable electric characteristics and essentially consists of indium zinc oxide. In addition, provided is a highly reliable semiconductor device which has stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film essentially consisting of indium zinc oxide has a hexagonal crystal structure in which the a-b plane is substantially parallel to a surface of the oxide semiconductor film and a rhombohedral crystal structure in which the a-b plane is substantially parallel to the surface of the oxide semiconductor film.

Abstract: An object is to provide a semiconductor device including an oxide semiconductor, which has stable electrical characteristics and high reliability. In a manufacturing process of a bottom-gate transistor including an oxide semiconductor layer, heat treatment in an atmosphere containing oxygen and heat treatment in vacuum are sequentially performed for dehydration or dehydrogenation of the oxide semiconductor layer. In addition, irradiation with light having a short wavelength is performed concurrently with the heat treatment, whereby elimination of hydrogen, OH, or the like is promoted. A transistor including an oxide semiconductor layer on which dehydration or dehydrogenation treatment is performed through such heat treatment has improved stability, so that variation in electrical characteristics of the transistor due to light irradiation or a bias-temperature stress (BT) test is suppressed.

Abstract: Manufactured is a transistor including an oxide semiconductor layer, a source electrode layer and a drain electrode layer overlapping with part of the oxide semiconductor layer, a gate insulating layer overlapping with the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode overlapping with part of the oxide semiconductor layer with the gate insulating layer provided therebetween, wherein, after the oxide semiconductor layer which is to be a channel formation region is irradiated with light and the light irradiation is stopped, a relaxation time of carriers in photoresponse characteristics of the oxide semiconductor layer has at least two kinds of modes: ?1 and ?2, ?1<?2 is satisfied, and ?2 is 300 seconds or less. In addition, a semiconductor device including the transistor is manufactured.

Abstract: An oxide semiconductor layer in which “safe” traps exist exhibits two kinds of modes in photoresponse characteristics. By using the oxide semiconductor layer, a transistor in which light deterioration is suppressed to the minimum and the electric characteristics are stable can be achieved. The oxide semiconductor layer exhibiting two kinds of modes in photoresponse characteristics has a photoelectric current value of 1 pA to 10 nA inclusive. When the average time ?1 until which carriers are captured by the “safe” traps is large enough, there are two kinds of modes in photoresponse characteristics, that is, a region where the current value falls rapidly and a region where the current value falls gradually, in the result of a change in photoelectric current over time.

Abstract: An object is, in a thin film transistor including an oxide semiconductor layer, to reduce contact resistance between the oxide semiconductor layer and source and drain electrode layers electrically connected to the oxide semiconductor layer. The source and drain electrode layers have a stacked-layer structure of two or more layers in which a layer in contact with the oxide semiconductor layer is formed using a metal whose work function is lower than the work function of the oxide semiconductor layer or an alloy containing such a metal. Layers other than the layer in contact with the oxide semiconductor layer of the source and drain electrode layers are formed using an element selected from Al, Cr, Cu, Ta, Ti, Mo, or W, an alloy containing any of these elements as a component, an alloy containing any of these elements in combination, or the like.

Abstract: Provided is an oxide semiconductor film which has more stable electric characteristics and essentially consists of indium zinc oxide. In addition, provided is a highly reliable semiconductor device which has stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film essentially consisting of indium zinc oxide has a hexagonal crystal structure in which the a-b plane is substantially parallel to a surface of the oxide semiconductor film and a rhombohedral crystal structure in which the a-b plane is substantially parallel to the surface of the oxide semiconductor film.

Abstract: To reduce defects in an oxide semiconductor film in a semiconductor device. To improve electrical characteristics of and reliability in the semiconductor device including an oxide semiconductor film. A method for manufacturing a semiconductor device includes the steps of forming a gate electrode and a gate insulating film over a substrate, forming an oxide semiconductor film over the gate insulating film, forming a pair of electrodes over the oxide semiconductor film, forming a first oxide insulating film over the oxide semiconductor film and the pair of electrodes by a plasma CVD method in which a film formation temperature is 280° C. or higher and 400° C. or lower, forming a second oxide insulating film over the first oxide insulating film, and performing heat treatment at a temperature of 150° C. to 400° C. inclusive, preferably 300° C. to 400° C. inclusive, further preferably 320° C. to 370° C. inclusive.

Abstract: Provided is an oxide semiconductor film which has more stable electric characteristics and essentially consists of indium zinc oxide. In addition, provided is a highly reliable semiconductor device which has stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film essentially consisting of indium zinc oxide has a hexagonal crystal structure in which the a-b plane is substantially parallel to a surface of the oxide semiconductor film and a rhombohedral crystal structure in which the a-b plane is substantially parallel to the surface of the oxide semiconductor film.

Abstract: Provided is an oxide semiconductor film which has more stable electric characteristics and essentially consists of indium zinc oxide. In addition, provided is a highly reliable semiconductor device which has stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film essentially consisting of indium zinc oxide has a hexagonal crystal structure in which the a-b plane is substantially parallel to a surface of the oxide semiconductor film and a rhombohedral crystal structure in which the a-b plane is substantially parallel to the surface of the oxide semiconductor film.

Abstract: An object is to reduce contact resistance between an oxide semiconductor layer and source and drain electrode layers electrically connected to the oxide semiconductor layer in a thin film transistor including the oxide semiconductor layer. The source and drain electrode layers have a stacked structure of two or more layers. In this stack of layers, a layer in contact with the oxide semiconductor layer is a thin indium layer or a thin indium-alloy layer. Note that the oxide semiconductor layer contains indium. A second layer or second and any of subsequent layers in the source and drain electrode layers are formed using an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W, an alloy containing any of these elements as a component, an alloy containing any of these elements in combination, or the like.

Abstract: Disclosed is a semiconductor device comprising a thin film transistor and wirings connected to the thin film transistor, in which the thin film transistor has a channel formation region in an oxide semiconductor layer, and a copper metal is used for at least one of a gate electrode, a source electrode, a drain electrode, a gate wiring, a source wiring, and a drain wiring. The extremely low off current of the transistor with the oxide semiconductor layer contributes to reduction in power consumption of the semiconductor device. Additionally, the use of the copper metal allows the combination of the semiconductor device with a display element to provide a display device with high display quality and negligible defects, which results from the low electrical resistance of the wirings and electrodes formed with the copper metal.

Abstract: An object is, in a thin film transistor including an oxide semiconductor layer, to reduce contact resistance between the oxide semiconductor layer and source and drain electrode layers electrically connected to the oxide semiconductor layer. The source and drain electrode layers have a stacked-layer structure of two or more layers in which a layer in contact with the oxide semiconductor layer is formed using an oxide of a metal whose work function is lower than the work function of the oxide semiconductor layer or an oxide of an alloy containing such a metal. Layers other than the layer in contact with the oxide semiconductor layer of the source and drain electrode layers are formed using an element selected from Al, Cr, Cu, Ta, Ti, Mo, or W, an alloy containing any of these elements as a component, an alloy containing any of these elements in combination, or the like.

Abstract: One embodiment of the present invention is a semiconductor device at least including an oxide semiconductor film, a gate insulating film in contact with the oxide semiconductor film, and a gate electrode overlapping with the oxide semiconductor film with the gate insulating film therebetween. The oxide semiconductor film has a spin density lower than 9.3×1016 spins/cm3 and a carrier density lower than 1×1015/cm3. The spin density is calculated from a peak of a signal detected at a g value (g) of around 1.93 by electron spin resonance spectroscopy. The oxide semiconductor film is formed by a sputtering method while bias power is supplied to the substrate side and self-bias voltage is controlled, and then subjected to heat treatment.

Abstract: Disclosed is a semiconductor device comprising a thin film transistor and wirings connected to the thin film transistor, in which the thin film transistor has a channel formation region in an oxide semiconductor layer, and a copper metal is used for at least one of a gate electrode, a source electrode, a drain electrode, a gate wiring, a source wiring, and a drain wiring. The extremely low off current of the transistor with the oxide semiconductor layer contributes to reduction in power consumption of the semiconductor device. Additionally, the use of the copper metal allows the combination of the semiconductor device with a display element to provide a display device with high display quality and negligible defects, which results from the low electrical resistance of the wirings and electrodes formed with the copper metal.

Abstract: Provided is an oxide semiconductor film which has more stable electric characteristics and essentially consists of indium zinc oxide. In addition, provided is a highly reliable semiconductor device which has stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film essentially consisting of indium zinc oxide has a hexagonal crystal structure in which the a-b plane is substantially parallel to a surface of the oxide semiconductor film and a rhombohedral crystal structure in which the a-b plane is substantially parallel to the surface of the oxide semiconductor film.