An object is to improve reliability of a semiconductor device. A semiconductor device including a driver circuit portion and a display portion (also referred to as a pixel portion) over the same substrate is provided. The driver circuit portion and the display portion include thin film transistors in which a semiconductor layer includes an oxide semiconductor; a first wiring; and a second wiring. The thin film transistors each include a source electrode layer and a drain electrode layer. In the thin film transistor in the driver circuit portion, the semiconductor layer is sandwiched between a gate electrode layer and a conductive layer. The first wiring and the second wiring are electrically connected to each other in an opening provided in a gate insulating film through an oxide conductive layer.

A semiconductor device includes first to third electrodes, a semiconductor member, first and second insulating members, a compound member, and a nitride member. The third electrode is between the first and second electrodes. The semiconductor member includes first and second semiconductor regions. The first semiconductor region includes first to fifth partial regions. The second semiconductor region includes first and second semiconductor portions. The first insulating member includes first and second insulating portions. The first semiconductor portion is between the fourth partial region and the first insulating portion. The second semiconductor portion is between the fifth partial region and the second insulating portion. The compound member includes first to third compound portions. The nitride member includes first to third nitride portions. The second insulating member includes first and second insulating regions. The first and second insulating regions are between the nitride regions and the third electrode.

Oxide layers which contain at least one metal element that is the same as that contained in an oxide semiconductor layer including a channel are formed in contact with the top surface and the bottom surface of the oxide semiconductor layer, whereby an interface state is not likely to be generated at each of an upper interface and a lower interface of the oxide semiconductor layer. Further, it is preferable that an oxide layer, which is formed using a material and a method similar to those of the oxide layers be formed over the oxide layers Accordingly, the interface state hardly influences the movement of electrons.

A semiconductor device includes an extremely thin semiconductor-on-insulator substrate (ETSOI) having a base substrate, a thin semiconductor layer and a buried dielectric therebetween. A device channel is formed in the thin semiconductor layer. Source and drain regions are formed at opposing positions relative to the device channel. The source and drain regions include an n-type material deposited on the buried dielectric within a thickness of the thin semiconductor layer. A gate structure is formed over the device channel.

A manufacturing method of a thin film transistor array panel according to an exemplary embodiment of the present invention includes forming an amorphous silicon thin film on a substrate. A lower region of the amorphous silicon thin film is crystallized to form a polycrystalline silicon thin film by irradiating a laser beam with an energy density of from about 150 mj/cm.sup.2 to about 250 mj/cm.sup.2 to the amorphous silicon thin film.

An oxide semiconductor film which has more stable electric conductivity is provided. The oxide semiconductor film comprises a crystalline region. The oxide semiconductor film has a first peak of electron diffraction intensity with a full width at half maximum of greater than or equal to 0.4 nm.sup.1 and less than or equal to 0.7 nm.sup.1 in a region where a magnitude of a scattering vector is greater than or equal to 3.3 nm.sup.1 and less than or equal to 4.1 nm.sup.1. The oxide semiconductor film has a second peak of electron diffraction intensity with a full width at half maximum of greater than or equal to 0.45 nm.sup.1 and less than or equal to 1.4 nm.sup.1 in a region where a magnitude of a scattering vector is greater than or equal to 5.5 nm.sup.1 and less than or equal to 7.1 nm.sup.1.

At least one of a plurality of transistors which are highly integrated in an element is provided with a back gate without increasing the number of manufacturing steps. In an element including a plurality of transistors which are longitudinally stacked, at least a transistor in an upper portion includes a metal oxide having semiconductor characteristics, a same layer as a gate electrode of a transistor in a lower portion is provided to overlap with a channel formation region of the transistor in an upper portion, and part of the same layer as the gate electrode functions as a back gate of the transistor in an upper portion. The transistor in a lower portion which is covered with an insulating layer is subjected to planarization treatment, whereby the gate electrode is exposed and connected to a layer functioning as source and drain electrodes of the transistor in an upper portion.

A method for fabricating a semiconductor device comprises patterning a strained fin from a strained layer of semiconductor material arranged on a substrate, depositing a first layer of semiconductor material on the fin and exposed portions of the substrate, patterning and etching to remove a portion of the first layer of semiconductor material and a portion of the fin to expose a portion of the substrate, depositing a second layer of semiconductor material on exposed portions of the substrate and the first layer of semiconductor material, and patterning and etching to remove a portion of the second layer of semiconductor material layer and the first layer of semiconductor material to define a dummy gate stack, the dummy gate stack is operative to substantially maintain the strain in the strained fin.

A method for forming a semiconductor device comprises forming a fin in a bulk semiconductor substrate and depositing a first insulator layer over portions of the bulk semiconductor substrate adjacent to the fin. The method further includes removing portions of the first insulator layer to reduce a thickness of the first insulator layer and expose a sidewall of the fin. An etch stop layer is deposited on the first insulator layer. A gate stack is formed over a channel region of the fin and over portions of the etch stop layer. A portion of the bulk semiconductor substrate is removed to expose portions of the etch stop layer and the fin, and a second insulator layer is deposited over exposed portions of the fin and the etch stop layer.

A method for forming a semiconductor device comprises forming a fin in a bulk semiconductor substrate and depositing a first insulator layer over portions of the bulk semiconductor substrate adjacent to the fin. The method further includes removing portions of the first insulator layer to reduce a thickness of the first insulator layer and expose a sidewall of the fin. An etch stop layer is deposited on the first insulator layer. A gate stack is formed over a channel region of the fin and over portions of the etch stop layer. A portion of the bulk semiconductor substrate is removed to expose portions of the etch stop layer and the fin, and a second insulator layer is deposited over exposed portions of the fin and the etch stop layer.