Abstract: A semiconductor device having favorable electrical characteristics is provided. The semiconductor device includes a conductor, a first insulator in contact with a side surface of the conductor, a second insulator in contact with a top surface of the conductor and a top surface of the first insulator, and an oxide over the second insulator. The oxide includes a region that overlaps with the conductor with the second insulator interposed therebetween. The maximum height of a roughness curve (Rz) of the top surface of the conductor is 6.0 nm or smaller. The region includes crystals, and c-axes of the crystals are aligned in the normal direction of the top surface of the conductor.

Abstract: A semiconductor device having favorable electrical characteristics is provided. The semiconductor device includes a conductor, a first insulator in contact with a side surface of the conductor, a second insulator in contact with a top surface of the conductor and a top surface of the first insulator, and an oxide over the second insulator. The oxide includes a region that overlaps with the conductor with the second insulator interposed therebetween. The maximum height of a roughness curve (Rz) of the top surface of the conductor is 6.0 nm or smaller. The region includes crystals, and c-axes of the crystals are aligned in the normal direction of the top surface of the conductor.

Abstract: A semiconductor device having favorable electrical characteristics is provided. The semiconductor device includes a conductor, a first insulator in contact with a side surface of the conductor, a second insulator in contact with a top surface of the conductor and a top surface of the first insulator, and an oxide over the second insulator. The oxide includes a region that overlaps with the conductor with the second insulator interposed therebetween. The maximum height of a roughness curve (Rz) of the top surface of the conductor is 6.0 nm or smaller. The region includes crystals, and c-axes of the crystals are aligned in the normal direction of the top surface of the conductor.

Abstract: A semiconductor device having favorable electrical characteristics is provided. The semiconductor device includes a conductor, a first insulator in contact with a side surface of the conductor, a second insulator in contact with a top surface of the conductor and a top surface of the first insulator, and an oxide over the second insulator. The oxide includes a region that overlaps with the conductor with the second insulator interposed therebetween. The maximum height of a roughness curve (Rz) of the top surface of the conductor is 6.0 nm or smaller. The region includes crystals, and c-axes of the crystals are aligned in the normal direction of the top surface of the conductor.

Abstract: A semiconductor device with a high on-state current is provided. The semiconductor device includes a first insulator, a first oxide over the first insulator, a second oxide over the first oxide, a first conductor and a second conductor over the second oxide, a third oxide over the second oxide, a second insulator over the third oxide, a third conductor that is located over the second insulator and overlaps with the third oxide, a third insulator that is located over the first insulator and in contact with a side surface of the first oxide, a side surface of the second oxide, a side surface of the first conductor, a top surface of the first conductor, a side surface of the second conductor, and a top surface of the second conductor, and a fourth insulator over the third conductor, the second insulator, the third oxide, and the third insulator. The fourth insulator is in contact with a top surface of each of the third conductor, the second insulator, and the third oxide.

Abstract: A semiconductor device having favorable electrical characteristics is provided. The semiconductor device includes a conductor, a first insulator in contact with a side surface of the conductor, a second insulator in contact with a top surface of the conductor and a top surface of the first insulator, and an oxide over the second insulator. The oxide includes a region that overlaps with the conductor with the second insulator interposed therebetween. The maximum height of a roughness curve (Rz) of the top surface of the conductor is 6.0 nm or smaller. The region includes crystals, and c-axes of the crystals are aligned in the normal direction of the top surface of the conductor.

Abstract: A semiconductor device with a high on-state current is provided. The semiconductor device includes a first insulator, a first oxide over the first insulator, a second oxide over the first oxide, a first conductor and a second conductor over the second oxide, a third oxide over the second oxide, a second insulator over the third oxide, a third conductor that is located over the second insulator and overlaps with the third oxide, a third insulator that is located over the first insulator and in contact with a side surface of the first oxide, a side surface of the second oxide, a side surface of the first conductor, a top surface of the first conductor, a side surface of the second conductor, and a top surface of the second conductor, and a fourth insulator over the third conductor, the second insulator, the third oxide, and the third insulator. The fourth insulator is in contact with a top surface of each of the third conductor, the second insulator, and the third oxide.

Abstract: A base insulating film is formed over a substrate. A first oxide semiconductor film is formed over the base insulating film, and then first heat treatment is performed to form a second oxide semiconductor film. Then, selective etching is performed to form a third oxide semiconductor film. An insulating film is formed over the first insulating film and the third oxide semiconductor film. A surface of the insulating film is polished to expose a surface of the third oxide semiconductor film, so that a sidewall insulating film is formed in contact with at least a side surface of the third oxide semiconductor film. Then, a source electrode and a drain electrode are formed over the sidewall insulating film and the third oxide semiconductor film. A gate insulating film and a gate electrode are formed.

Abstract: A minute transistor and the method of manufacturing the minute transistor. A source electrode layer and a drain electrode layer are each formed in a corresponding opening formed in an insulating layer covering a semiconductor layer. The opening of the source electrode layer and the opening of the drain electrode layer are formed separately in two distinct steps. The source electrode layer and the drain electrode layer are formed by depositing a conductive layer over the insulating layer and in the openings, and subsequently removing the part located over the insulating layer by polishing. This manufacturing method allows for the source electrode later and the drain electrode layer to be formed close to each other and close to a channel forming region of the semiconductor layer. Such a structure leads to a transistor having high electrical characteristics and a high manufacturing yield even in the case of a minute structure.

Abstract: A transistor including an oxide semiconductor film, which has stable electric characteristics is provided. A transistor including an oxide semiconductor film, which has excellent on-state characteristics is also provided. A semiconductor device in which an oxide semiconductor film having low resistance is formed and the resistance of a channel region of the oxide semiconductor film is increased. Note that an oxide semiconductor film is subjected to a process for reducing the resistance to have low resistance. The process for reducing the resistance of the oxide semiconductor film may be a laser process or heat treatment at a temperature higher than or equal to 450° C. and lower than or equal to 740° C., for example. A process for increasing the resistance of the channel region of the oxide semiconductor film having low resistance may be performed by plasma oxidation or implantation of oxygen ions, for example.

Abstract: A first conductor is formed over a substrate. A first insulator is formed over the first conductor. A second insulator including aluminum oxide is formed over the first insulator. A third insulator is formed in contact with a top surface of the second insulator. A first opening portion reaching the first conductor is provided in the first to third insulators. A second conductor is formed over the third insulator and in the first opening portion. A third conductor is formed in the first opening portion by removing part of the second conductor over the third insulator so that a surface of the third conductor is parallel to a bottom surface of the substrate. A first transistor including an oxide semiconductor is formed over the third insulator.

Abstract: A transistor including an oxide semiconductor film, which has stable electric characteristics is provided. A transistor including an oxide semiconductor film, which has excellent on-state characteristics is also provided. A semiconductor device in which an oxide semiconductor film having low resistance is formed and the resistance of a channel region of the oxide semiconductor film is increased. Note that an oxide semiconductor film is subjected to a process for reducing the resistance to have low resistance. The process for reducing the resistance of the oxide semiconductor film may be a laser process or heat treatment at a temperature higher than or equal to 450° C. and lower than or equal to 740° C., for example. A process for increasing the resistance of the channel region of the oxide semiconductor film having low resistance may be performed by plasma oxidation or implantation of oxygen ions, for example.

Abstract: A transistor including an oxide semiconductor film, which has stable electric characteristics is provided. A transistor including an oxide semiconductor film, which has excellent on-state characteristics is also provided. A semiconductor device in which an oxide semiconductor film having low resistance is formed and the resistance of a channel region of the oxide semiconductor film is increased. Note that an oxide semiconductor film is subjected to a process for reducing the resistance to have low resistance. The process for reducing the resistance of the oxide semiconductor film may be a laser process or heat treatment at a temperature higher than or equal to 450° C. and lower than or equal to 740° C., for example. A process for increasing the resistance of the channel region of the oxide semiconductor film having low resistance may be performed by plasma oxidation or implantation of oxygen ions, for example.

Abstract: A base insulating film is formed over a substrate. A first oxide semiconductor film is formed over the base insulating film, and then first heat treatment is performed to form a second oxide semiconductor film. Then, selective etching is performed to form a third oxide semiconductor film. An insulating film is formed over the first insulating film and the third oxide semiconductor film. A surface of the insulating film is polished to expose a surface of the third oxide semiconductor film, so that a sidewall insulating film is formed in contact with at least a side surface of the third oxide semiconductor film. Then, a source electrode and a drain electrode are formed over the sidewall insulating film and the third oxide semiconductor film. A gate insulating film and a gate electrode are formed.

Abstract: A minute transistor and the method of manufacturing the minute transistor. A source electrode layer and a drain electrode layer are each formed in a corresponding opening formed in an insulating layer covering a semiconductor layer. The opening of the source electrode layer and the opening of the drain electrode layer are formed separately in two distinct steps. The source electrode layer and the drain electrode layer are formed by depositing a conductive layer over the insulating layer and in the openings, and subsequently removing the part located over the insulating layer by polishing. This manufacturing method allows for the source electrode later and the drain electrode layer to be formed close to each other and close to a channel forming region of the semiconductor layer. Such a structure leads to a transistor having high electrical characteristics and a high manufacturing yield even in the case of a minute structure.

Abstract: A base insulating film is formed over a substrate. A first oxide semiconductor film is formed over the base insulating film, and then first heat treatment is performed to form a second oxide semiconductor film. Then, selective etching is performed to form a third oxide semiconductor film. An insulating film is formed over the first insulating film and the third oxide semiconductor film. A surface of the insulating film is polished to expose a surface of the third oxide semiconductor film, so that a sidewall insulating film is formed in contact with at least a side surface of the third oxide semiconductor film. Then, a source electrode and a drain electrode are formed over the sidewall insulating film and the third oxide semiconductor film. A gate insulating film and a gate electrode are formed.

Abstract: A minute transistor and the method of manufacturing the minute transistor. A source electrode layer and a drain electrode layer are each formed in a corresponding opening formed in an insulating layer covering a semiconductor layer. The opening of the source electrode layer and the opening of the drain electrode layer are formed separately in two distinct steps. The source electrode layer and the drain electrode layer are formed by depositing a conductive layer over the insulating layer and in the openings, and subsequently removing the part located over the insulating layer by polishing. This manufacturing method allows for the source electrode later and the drain electrode layer to be formed close to each other and close to a channel forming region of the semiconductor layer. Such a structure leads to a transistor having high electrical characteristics and a high manufacturing yield even in the case of a minute structure.

Abstract: An object is to provide a semiconductor device having excellent characteristics, in which a channel layer includes an oxide semiconductor with high crystallinity. In addition, a semiconductor device including a base film with improved planarity is provided. CMP treatment is performed on the base film of the transistor and plasma treatment is performed thereon after the CMP treatment, whereby the base film can have a center line average roughness Ra75 of less than 0.1 nm. The oxide semiconductor layer with high crystallinity is formed over the base film having planarity, which is obtained by the combination of the plasma treatment and the CMP treatment, thereby improving the characteristics of the semiconductor device.

Abstract: A transistor including an oxide semiconductor film, which has stable electric characteristics is provided. A transistor including an oxide semiconductor film, which has excellent on-state characteristics is also provided. A semiconductor device in which an oxide semiconductor film having low resistance is formed and the resistance of a channel region of the oxide semiconductor film is increased. Note that an oxide semiconductor film is subjected to a process for reducing the resistance to have low resistance. The process for reducing the resistance of the oxide semiconductor film may be a laser process or heat treatment at a temperature higher than or equal to 450° C. and lower than or equal to 740° C., for example. A process for increasing the resistance of the channel region of the oxide semiconductor film having low resistance may be performed by plasma oxidation or implantation of oxygen ions, for example.

Abstract: A minute transistor and the method of manufacturing the minute transistor. A source electrode layer and a drain electrode layer are each formed in a corresponding opening formed in an insulating layer covering a semiconductor layer. The opening of the source electrode layer and the opening of the drain electrode layer are formed separately in two distinct steps. The source electrode layer and the drain electrode layer are formed by depositing a conductive layer over the insulating layer and in the openings, and subsequently removing the part located over the insulating layer by polishing. This manufacturing method allows for the source electrode later and the drain electrode layer to be formed close to each other and close to a channel forming region of the semiconductor layer. Such a structure leads to a transistor having high electrical characteristics and a high manufacturing yield even in the case of a minute structure.