Disclosed is a display device including a transistor showing extremely low off current. In order to reduce the off current, a semiconductor material whose band gap is greater than that of a silicon semiconductor is used for forming a transistor, and the concentration of an impurity which serves as a carrier donor of the semiconductor material is reduced. Specifically, an oxide semiconductor whose band gap is greater than or equal to 2 eV, preferably greater than or equal to 2.5 eV, more preferably greater than or equal to 3 eV is used for a semiconductor layer of a transistor, and the concentration of an impurity which serves as a carrier donor included is reduced. Consequently, the off current of the transistor per micrometer in channel width can be reduced to lower than 10 zA/μm at room temperature and lower than 100 zA/μm at 85° C.

A liquid crystal display device is provided with a thin film transistor which includes a gate electrode film that is provided in a first electrode layer located over a first insulating layer, a semiconductor film that is disposed over the gate electrode film via a second insulating layer, a drain electrode and a source electrode that are provided in a second electrode layer located over the semiconductor film and are in contact with an upper surface of the semiconductor film, and a light blocking film that is disposed under the first insulating layer. At least a part thereof overlaps the semiconductor film and the gate electrode film in a plan view. One of the drain electrode and the source electrode is connected to a gate line, and the light blocking film is electrically connected to the source electrode.

An active matrix organic light emitting diode (OLED) display device includes an array of pixels, each pixel including an OLED, a driving transistor (DT) coupled to drive current through the OLED, a storage capacitor, and a scanning transistor (ST) coupled to control charge on the storage capacitor corresponding to a data voltage for said pixel. The display device also includes a timing controller configured to control the ST of each pixel to update the charge stored on the storage capacitor of each pixel at a frame rate including at least one frequency within a range of 1-10 Hertz (Hz).

A semiconductor device using oxide semiconductor with favorable electrical characteristics, or a highly reliable semiconductor device is provided. A semiconductor device is manufactured by: forming an oxide semiconductor layer over an insulating surface; forming source and drain electrodes over the oxide semiconductor layer; forming an insulating film and a conductive film in this order over the oxide semiconductor layer and the source and drain electrodes; etching part of the conductive film and insulating film to form a gate electrode and a gate insulating layer, and etching part of the upper portions of the source and drain electrodes to form a first covering layer containing a constituent element of the source and drain electrodes and in contact with the side surface of the gate insulating layer; oxidizing the first covering layer to form a second covering layer; and forming a protective insulating layer containing an oxide over the second covering layer.

To provide a miniaturized semiconductor device with low power consumption. A method for manufacturing a wiring layer includes the following steps: forming a second insulator over a first insulator; forming a third insulator over the second insulator; forming an opening in the third insulator so that it reaches the second insulator; forming a first conductor over the third insulator and in the opening; forming a second conductor over the first conductor; and after forming the second conductor, performing polishing treatment to remove portions of the first and second conductors above a top surface of the third insulator. An end of the first conductor is at a level lower than or equal to the top level of the opening. The top surface of the second conductor is at a level lower than or equal to that of the end of the first conductor.

Disclosed is a display device including a transistor showing extremely low off current. In order to reduce the off current, a semiconductor material whose band gap is greater than that of a silicon semiconductor is used for forming a transistor, and the concentration of an impurity which serves as a carrier donor of the semiconductor material is reduced. Specifically, an oxide semiconductor whose band gap is greater than or equal to 2 eV, preferably greater than or equal to 2.5 eV, more preferably greater than or equal to 3 eV is used for a semiconductor layer of a transistor, and the concentration of an impurity which serves as a carrier donor included is reduced. Consequently, the off current of the transistor per micrometer in channel width can be reduced to lower than 10 zA/μm at room temperature and lower than 100 zA/μm at 85° C.

According to one embodiment, a semiconductor device includes an insulating substrate, an oxide semiconductor layer, a gate insulating film, a gate electrode, a first insulating film and a second insulating film. The oxide semiconductor layer is provided on the insulating substrate and includes first and second low-resistance regions and a high-resistance region between the first and second low-resistance regions. The gate insulating film is provided on the high-resistance region of the oxide semiconductor layer. The gate electrode is provided on the gate insulating film. The first insulating film is provided above the gate electrode, gate insulating film and first and second low-resistance regions of the oxide semiconductor layer, and contains at least fluorine. The second insulating film is provided on the first insulating film, and contains aluminum.

The present disclosure is directed to methods for the fabrication of gate-all-around (GAA) field effect transistors (FETs) with low power consumption. The method includes depositing a first and a second epitaxial layer on a substrate and etching trench openings in the first and second epitaxial layers and the substrate. The method further includes removing, through the trench openings, portions of the first epitaxial layer to form a gap between the second epitaxial layer and the substrate and depositing, through the trench openings, a first dielectric to fill the gap and form an isolation structure. In addition, the method includes depositing a second dielectric in the trench openings to form trench isolation structures and forming a transistor structure on the second epitaxial layer.

To provide a miniaturized semiconductor device with low power consumption. A method for manufacturing a wiring layer includes the following steps: forming a second insulator over a first insulator; forming a third insulator over the second insulator; forming an opening in the third insulator so that it reaches the second insulator; forming a first conductor over the third insulator and in the opening; forming a second conductor over the first conductor; and after forming the second conductor, performing polishing treatment to remove portions of the first and second conductors above a top surface of the third insulator. An end of the first conductor is at a level lower than or equal to the top level of the opening. The top surface of the second conductor is at a level lower than or equal to that of the end of the first conductor.

The present application relates to an active switch, a manufacturing method thereof and a display device. The manufacturing method of the active switch includes: sequentially forming a gate electrode, a gate insulating layer, an active layer, a semiconductor composite layer and a source electrode and a drain electrode on a substrate. The semiconductor composite layer includes a first N-type heavily doped amorphous silicon layer, a first N-type lightly doped amorphous silicon layer, a second N-type heavily doped amorphous silicon layer and a second N-type lightly doped amorphous silicon layer which are sequentially stacked, where the ion doping concentration of the first N-type heavily doped amorphous silicon layer is lower than that of the second N-type heavily doped amorphous silicon layer, and the ion doping concentration of the first N-type lightly doped amorphous silicon layer is higher than that of the second N-type lightly doped amorphous silicon layer.