Abstract: A semiconductor device includes a pixel portion having a first thin film transistor and a driver circuit having a second thin film transistor. Each of the first thin film transistor and the second thin film transistor includes a gate electrode layer, a gate insulating layer, a semiconductor layer, a source electrode layer, and a drain electrode layer. Each of the layers of the first thin film transistor has a light-transmitting property. Materials of the gate electrode layer, the source electrode layer and the drain electrode layer of the first thin film transistor are different from those of the second transistor, and each of the resistances of the second thin film transistor is lower than that of the first thin film transistor.

Abstract: A double-wall pipe includes an outer pipe, and an inner pipe disposed inside the outer pipe. An outer wall of the inner pipe has thereon a ridge portion, which defines a groove portion extending in a longitudinal direction of the inner pipe. The outer pipe and the inner pipe are bent to have a straight portion extending straightly, and a bend portion bent from the straight portion. In the straight portion, the outer pipe has an inside diameter that is larger than an outside diameter of an imaginary cylinder defined by an outer surface of the ridge portion of the inner pipe. Furthermore, the ridge portion of the inner pipe contacts an inside surface of the outer pipe to be radially squeezed and held by the outer pipe, in the bend portion. The double-wall pipe can be suitably used for a refrigerant cycle device.

Abstract: An object is to manufacture a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which an oxide semiconductor film is used for a semiconductor layer including a channel formation region, heat treatment (for dehydration or dehydrogenation) is performed to improve the purity of the oxide semiconductor film and reduce impurities including moisture or the like. After that, slow cooling is performed under an oxygen atmosphere. Besides impurities including moisture or the like exiting in the oxide semiconductor film, heat treatment causes reduction of impurities including moisture or the like exiting in a gate insulating layer and those in interfaces between the oxide semiconductor film and films which are provided over and below the oxide semiconductor and in contact therewith.

Abstract: A semiconductor device including a thin film transistor which includes an oxide semiconductor layer and has high electric characteristics and reliability. Film deposition is performed using an oxide semiconductor target containing an insulator (an insulating oxide, an insulating nitride, silicon oxynitride, aluminum oxynitride, or the like), typically SiO2, so that the semiconductor device in which the Si-element concentration in the thickness direction of the oxide semiconductor layer has a gradient which increases in accordance with an increase in a distance from a gate electrode is realized.

Abstract: It is an object to provide a highly reliable semiconductor device which includes a thin film transistor having stable electric characteristics. It is another object to manufacture a highly reliable semiconductor device at lower cost with high productivity. In a method for manufacturing a semiconductor device which includes a thin film transistor where a semiconductor layer having a channel formation region, a source region, and a drain region are formed using an oxide semiconductor layer, heat treatment (heat treatment for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor layer and reduce impurities such as moisture. Moreover, the oxide semiconductor layer subjected to the heat treatment is slowly cooled under an oxygen atmosphere.

Abstract: An oxide semiconductor film which has more stable electric conductivity is provided. Further, a semiconductor device which has stable electric characteristics and high reliability is provided by using the oxide semiconductor film. An oxide semiconductor film includes a crystalline region, and the crystalline region includes a crystal in which an a-b plane is substantially parallel with a surface of the film and a c-axis is substantially perpendicular to the surface of the film; the oxide semiconductor film has stable electric conductivity and is more electrically stable with respect to irradiation with visible light, ultraviolet light, and the like. By using such an oxide semiconductor film for a transistor, a highly reliable semiconductor device having stable electric characteristics can be provided.

Abstract: An object is to provide a semiconductor device having stable electric characteristics in which an oxide semiconductor is used. An oxide semiconductor layer is subjected to heat treatment for dehydration or dehydrogenation treatment in a nitrogen gas or an inert gas atmosphere such as a rare gas (e.g., argon or helium) or under reduced pressure and to a cooling step for treatment for supplying oxygen in an atmosphere of oxygen, an atmosphere of oxygen and nitrogen, or the air (having a dew point of preferably lower than or equal to ?40° C., still preferably lower than or equal to ?50° C.) atmosphere. The oxide semiconductor layer is thus highly purified, whereby an i-type oxide semiconductor layer is formed. A semiconductor device including a thin film transistor having the oxide semiconductor layer is manufactured.

Abstract: It is an object to provide a highly reliable semiconductor device which includes a thin film transistor having stable electric characteristics. It is another object to manufacture a highly reliable semiconductor device at lower cost with high productivity. In a method for manufacturing a semiconductor device which includes a thin film transistor where a semiconductor layer including a channel formation region using an oxide semiconductor layer, a source region, and a drain region are formed using an oxide semiconductor layer, heat treatment for reducing impurities such as moisture (heat treatment for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor layer.

Abstract: An oxide semiconductor film which has more stable electric conductivity is provided. Further, a semiconductor device which has stable electric characteristics and high reliability is provided by using the oxide semiconductor film. An oxide semiconductor film includes a crystalline region, and the crystalline region includes a crystal in which an a-b plane is substantially parallel with a surface of the film and a c-axis is substantially perpendicular to the surface of the film; the oxide semiconductor film has stable electric conductivity and is more electrically stable with respect to irradiation with visible light, ultraviolet light, and the like. By using such an oxide semiconductor film for a transistor, a highly reliable semiconductor device having stable electric characteristics can be provided.

Abstract: There has been a problem that difference in refractive index between an opposite substrate or a moisture barrier layer provided thereover, and air is maintained large, and light extraction efficiency is low. Further, there has been a problem that peeling or cracking due to the moisture barrier layer is easily generated, which leads to deteriorate the reliability and lifetime of a light-emitting element. A light-emitting element comprises a pixel electrode, an electroluminescent layer, a transparent electrode, a passivation film, a stress relieving layer, and a low refractive index layer, all of which are stacked sequentially. The stress relieving layer serves to prevent peeling of the passivation film. The low refractive index layer serves to reduce reflectivity of light generated in the electroluminescent layer in emitting to air. Therefore, a light-emitting element with high reliability and long lifetime and a display device using the light-emitting element can be provided.

Abstract: A semiconductor device having a novel structure or a method for manufacturing the semiconductor device is provided. For example, the reliability of a transistor which is driven at high voltage or large current is improved. For improvement of the reliability of the transistor, a buffer layer is provided between a drain electrode layer (or a source electrode layer) and an oxide semiconductor layer such that the end portion of the buffer layer is beyond the side surface of the drain electrode layer (or the source electrode layer) when seen in a cross section, whereby the buffer layer can relieve the concentration of electric field. The buffer layer is a single layer or a stacked layer including a plurality of layers, and includes, for example, an In—Ga—Zn—O film containing nitrogen, an In—Sn—O film containing nitrogen, an In—Sn—O film containing SiOx, or the like.

Abstract: An object is to manufacture and provide a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which a semiconductor layer including a channel formation region serves as an oxide semiconductor film, heat treatment for reducing impurities such as moisture (heat treatment for dehydration or dehydrogenation) is performed after an oxide insulating film serving as a protective film is formed in contact with an oxide semiconductor layer. Then, the impurities such as moisture, which exist not only in a source electrode layer, in a drain electrode layer, in a gate insulating layer, and in the oxide semiconductor layer but also at interfaces between the oxide semiconductor film and upper and lower films which are in contact with the oxide semiconductor layer, are reduced.

Abstract: A semiconductor device including a thin film transistor which includes an oxide semiconductor layer and has high electric characteristics and reliability. Film deposition is performed using an oxide semiconductor target containing an insulator (an insulating oxide, an insulating nitride, silicon oxynitride, aluminum oxynitride, or the like), typically SiO2, so that the semiconductor device in which the Si-element concentration in the thickness direction of the oxide semiconductor layer has a gradient which increases in accordance with an increase in a distance from a gate electrode is realized.

Abstract: An object is to provide a high reliable semiconductor device including a thin film transistor having stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which an oxide semiconductor film is used for a semiconductor layer including a channel formation region, heat treatment (which is for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor film and reduce impurities such as moisture. Besides impurities such as moisture existing in the oxide semiconductor film, heat treatment causes reduction of impurities such as moisture existing in the gate insulating layer and those in interfaces between the oxide semiconductor film and films which are provided over and below the oxide semiconductor film and are in contact with the oxide semiconductor film.

Abstract: It is an object to provide a highly reliable semiconductor device which includes a thin film transistor having stable electric characteristics. It is another object to manufacture a highly reliable semiconductor device at lower cost with high productivity. In a method for manufacturing a semiconductor device which includes a thin film transistor where a semiconductor layer having a channel formation region, a source region, and a drain region are formed using an oxide semiconductor layer, heat treatment (heat treatment for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor layer and reduce impurities such as moisture. Moreover, the oxide semiconductor layer subjected to the heat treatment is slowly cooled under an oxygen atmosphere.

Abstract: An object is to manufacture a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which an oxide semiconductor film is used for a semiconductor layer including a channel formation region, heat treatment (for dehydration or dehydrogenation) is performed to improve the purity of the oxide semiconductor film and reduce impurities including moisture or the like. After that, slow cooling is performed under an oxygen atmosphere. Besides impurities including moisture or the like exiting in the oxide semiconductor film, heat treatment causes reduction of impurities including moisture or the like exiting in a gate insulating layer and those in interfaces between the oxide semiconductor film and films which are provided over and below the oxide semiconductor and in contact therewith.

Abstract: It is an object to provide a highly reliable semiconductor device which includes a thin film transistor having stable electric characteristics. It is another object to manufacture a highly reliable semiconductor device at lower cost with high productivity. In a method for manufacturing a semiconductor device which includes a thin film transistor where a semiconductor layer including a channel formation region using an oxide semiconductor layer, a source region, and a drain region are formed using an oxide semiconductor layer, heat treatment for reducing impurities such as moisture (heat treatment for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor layer.

Abstract: An object is to provide a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which an oxide semiconductor film is used for a semiconductor layer including a channel formation region, impurities such as moisture existing in the gate insulating layer are reduced before formation of the oxide semiconductor film, and then heat treatment (heat treatment for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor film and reduce impurities such as moisture. After that, slow cooling is performed in an oxygen atmosphere. Besides impurities such as moisture existing in the gate insulating layer and the oxide semiconductor film, impurities such as moisture existing at interfaces between the oxide semiconductor film and upper and lower films provided in contact therewith are reduced.

Abstract: It is an object to provide a highly reliable semiconductor device, a semiconductor device with low power consumption, a semiconductor device with high productivity, and a method for manufacturing such a semiconductor device. Impurities left remaining in an oxide semiconductor layer are removed without generating oxygen deficiency, and the oxide semiconductor layer is purified to have an extremely high purity. Specifically, after oxygen is added to the oxide semiconductor layer, heat treatment is performed on the oxide semiconductor layer to remove the impurities. In order to add oxygen, it is preferable to use a method in which oxygen having high energy is added by an ion implantation method, an ion doping method, or the like.

Abstract: An object is to provide a semiconductor device having stable electric characteristics in which an oxide semiconductor is used. An oxide semiconductor layer is subjected to heat treatment for dehydration or dehydrogenation treatment in a nitrogen gas or an inert gas atmosphere such as a rare gas (e.g., argon or helium) or under reduced pressure and to a cooling step for treatment for supplying oxygen in an atmosphere of oxygen, an atmosphere of oxygen and nitrogen, or the air (having a dew point of preferably lower than or equal to ?40° C., still preferably lower than or equal to ?50° C.) atmosphere. The oxide semiconductor layer is thus highly purified, whereby an i-type oxide semiconductor layer is formed. A semiconductor device including a thin film transistor having the oxide semiconductor layer is manufactured.