A display device includes a display element, a transistor configured to drive the display element, the transistor including a channel region, and a retention capacitor. An oxide semiconductor film is provided in areas across the transistor and the retention capacitor, the oxide semiconductor film including a first region formed in the channel region of the transistor, and a second region having a lower resistance than that of the first region. The second region is formed in the areas of the transistor and retention capacitor other than in the channel region.

A method of manufacturing a substrate includes: irradiating, along a first path, a laser beam emitted from a source onto a substrate, wherein the substrate includes a target layer of the laser beam, and wherein the substrate is disposed on a stage; and irradiating, along a second path, a portion the laser beam, which was emitted from the source and reached the target layer, by reflecting the laser beam back onto the target layer using a reflection mirror. An area of a second region of the target layer is greater than an area of a first region of the target layer, wherein the laser beam is irradiated along the second path in the second region, and the laser beam is irradiated along the first path in the first region.

A schottky barrier diode element having a silicon (Si) substrate, an oxide semiconductor layer and a schottky electrode layer, wherein the oxide semiconductor layer includes a polycrystalline and/or amorphous oxide semiconductor having a band gap of 3.0 eV or more and 5.6 eV or less.

To give favorable electrical characteristics to a semiconductor device. The semiconductor device includes an insulating layer, a semiconductor layer over the insulating layer, a pair of electrodes over the semiconductor layer and each electrically connected to the semiconductor layer, a gate electrode over the semiconductor layer, and a gate insulating layer between the semiconductor layer and the gate electrode. The insulating layer includes an island-shaped projecting portion. A top surface of the projecting portion of the insulating layer is in contact with a bottom surface of the semiconductor layer, and is positioned on an inner side of the semiconductor layer when seen from above. The pair of electrodes covers part of a top surface and part of side surfaces of the semiconductor layer. Furthermore, the gate electrode and the gate insulating layer cover side surfaces of the projecting portion of the insulating layer.

An imaging element has a laminated structure including a first electrode, a light-receiving layer formed on the first electrode, and a second electrode formed on the light-receiving layer. The second electrode is made of a transparent amorphous oxide having a conductive property.

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.

An object is to provide a semiconductor device with a novel structure. The semiconductor device includes a first wiring; a second wiring; a third wiring; a fourth wiring; a first transistor having a first gate electrode, a first source electrode, and a first drain electrode; and a second transistor having a second gate electrode, a second source electrode, and a second drain electrode. The first transistor is provided in a substrate including a semiconductor material. The second transistor includes an oxide semiconductor layer.

A first transistor, a second transistor, a third transistor, a fourth transistor are provided. In the first transistor, a first terminal is electrically connected to a first wiring; a second terminal is electrically connected to a gate terminal of the second transistor; a gate terminal is electrically connected to a fifth wiring. In the second transistor, a first terminal is electrically connected to a third wiring; a second terminal is electrically connected to a sixth wiring. In the third transistor, a first terminal is electrically connected to a second wiring; a second terminal is electrically connected to the gate terminal of the second transistor; a gate terminal is electrically connected to a fourth wiring. In the fourth transistor, a first terminal is electrically connected to the second wiring; a second terminal is electrically connected to the sixth wiring; a gate terminal is connected to the fourth wiring.

An object is to provide a semiconductor device having good electrical characteristics. A gate insulating layer having a hydrogen concentration less than 610.sup.20 atoms/cm.sup.3 and a fluorine concentration greater than or equal to 110.sup.20 atoms/cm.sup.3 is used as a gate insulating layer in contact with an oxide semiconductor layer forming a channel region, so that the amount of hydrogen released from the gate insulating layer can be reduced and diffusion of hydrogen into the oxide semiconductor layer can be prevented. Further, hydrogen present in the oxide semiconductor layer can be eliminated with the use of fluorine; thus, the hydrogen content in the oxide semiconductor layer can be reduced. Consequently, the semiconductor device having good electrical characteristics can be provided.

Processes and overturned thin film device structures generally include a metal gate having a concave shape defined by three faces. The processes generally include forming the overturned thin film device structures such that the channel self-aligns to the metal gate and the contacts can be self-aligned to the sacrificial material.