An object is to control composition and a defect of an oxide semiconductor, another object is to increase a field effect mobility of a thin film transistor and to obtain a sufficient on-off ratio with a reduced off current. A solution is to employ an oxide semiconductor whose composition is represented by InMO.sub.3(ZnO).sub.m, where M is one or a plurality of elements selected from Ga, Fe, Ni, Mn, Co, and Al, and m is preferably a non-integer number of greater than 0 and less than 1. The concentration of Zn is lower than the concentrations of In and M. The oxide semiconductor has an amorphous structure. Oxide and nitride layers can be provided to prevent pollution and degradation of the oxide semiconductor.

A semiconductor device includes a gate electrode on a substrate, a gate insulating film on the gate electrode, an oxide semiconductor film via the gate insulating film on the gate electrode, a source electrode and a drain electrode on the oxide semiconductor film, a protective film provided on the source electrode and the drain electrode; and a conductive layer provided on the protective film and overlapped on the oxide semiconductor layer. The protective film includes a first silicon oxide film and a first silicon nitride film. The first oxide film is in contact with the oxide semiconductor layer. The gate insulating film includes a second silicon nitride film and a second silicon oxide film. The second silicon oxide film is in contact with the oxide semiconductor layer. The oxide semiconductor layer has a first region located between the source electrode and the drain electrode in a plan view.

An object is to improve field effect mobility of a thin film transistor using an oxide semiconductor. Another object is to suppress increase in off current even in a thin film transistor with improved field effect mobility. In a thin film transistor using an oxide semiconductor layer, by forming a semiconductor layer having higher electrical conductivity and a smaller thickness than the oxide semiconductor layer between the oxide semiconductor layer and a gate insulating layer, field effect mobility of the thin film transistor can be improved, and increase in off current can be suppressed.

In a semiconductor device using a transistor including an oxide semiconductor, a change in electrical characteristics is inhibited and reliability is improved. The transistor includes a first gate electrode; a first insulating film over the first gate electrode; an oxide semiconductor film over the first insulating film; a source electrode electrically connected to the oxide semiconductor film; a drain electrode electrically connected to the oxide semiconductor film; a second insulating film over the oxide semiconductor film, the source electrode, and the drain electrode; and a second gate electrode over the second insulating film. The second insulating film includes oxygen. The second gate electrode includes the same metal element as at least one of metal elements of the oxide semiconductor film and has a region thinner than the oxide semiconductor film.

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 invention provides two methods for crystallizing a metal oxide semiconductor layer and a semiconductor structure. The first crystallization method is treating an amorphous metal oxide semiconductor layer including indium with oxygen at a pressure of about 550 mtorr to about 5000 mtorr and at a temperature of about 200° C. to about 750° C. The second crystallization method is, firstly, sequentially forming a first amorphous metal oxide semiconductor layer, an aluminum layer, and a second amorphous metal oxide semiconductor layer on a substrate, and, secondly, treating the first amorphous metal oxide semiconductor layer, the aluminum layer, and the second amorphous metal oxide semiconductor layer with an inert gas at a temperature of about 350° C. to about 650° C.

Disclosed are an oxide thin film transistor (TFT), a method of manufacturing the same, and a display panel and a display device using the same, in which a first conductor and a second conductor are provided at end portions of a semiconductor layer formed of oxide semiconductor. The first conductor and second conductor are electrically connected to a first electrode and a second electrode, and covered by a gate insulation layer. The oxide TFT includes a semiconductor layer provided on a buffer and including an oxide semiconductor, a gate insulation layer covering the semiconductor layer and the buffer, a gate electrode provided on the gate insulation layer to overlap a portion of the semiconductor layer, and a passivation layer covering the gate and the gate insulation layer.

A method for making an array substrate includes the following steps: forming a poly-silicon semiconductor layer on a substrate; forming a buffer layer on the substrate; depositing a first metal layer, and patterning the first metal layer to form gate electrodes for a driving TFT, a switch TFT, and a poly-silicon TFT; forming a first gate insulator layer; forming a second gate insulator layer; defining through holes passing through the buffer layer, the first gate insulator layer, and the second gate insulator layer to expose the poly-silicon semiconductor layer; depositing a metal oxide layer to form a first metal oxide semiconductor layer; and depositing a second metal layer to form source electrodes and drain electrodes for the driving TFT, the switch TFT, and the poly-silicon TFT.

An array substrate, a fabrication method thereof, and a display panel are provided. The array substrate comprises a substrate, and a plurality of thin-film-transistors, which includes an active layer formed on the substrate including a source region, a drain region, and a channel region located between the source region and the drain region, a source electrode metal contact layer, a drain electrode metal contact layer, a barrier layer formed on a side of the active layer facing away from the substrate, a source electrode formed on a side of the source electrode metal contact layer facing away from active layer, a drain electrode formed on a side of the drain electrode metal contact layer facing away from the active layer, and a gate electrode insulated from the barrier layer and formed on a side of the barrier layer facing away from the active layer.

Disclosed is a power storage element including a positive electrode current collector layer and a negative electrode current collector layer which are arranged on the same plane and can be formed through a simple process. The power storage element further includes a positive electrode active material layer on the positive electrode current collector layer; a negative electrode active material layer on the negative electrode current collector layer; and a solid electrolyte layer in contact with at least the positive electrode active material layer and the negative electrode active material layer. The positive electrode active material layer and the negative electrode active material layer are formed by oxidation treatment.