Defects in an oxide semiconductor film are reduced in a semiconductor device including the oxide semiconductor film. The electrical characteristics of a semiconductor device including an oxide semiconductor film are improved. The reliability of a semiconductor device including an oxide semiconductor film is improved. A semiconductor device including an oxide semiconductor layer; a metal oxide layer in contact with the oxide semiconductor layer, the metal oxide layer including an In-M oxide (M is Ti, Ga, Y, Zr, La, Ce, Nd, or Hf); and a conductive layer in contact with the metal oxide layer, the conductive layer including copper, aluminum, gold, or silver is provided. In the semiconductor device, y/(x+y) is greater than or equal to 0.75 and less than 1 where the atomic ratio of In to M included in the metal oxide layer is In:M=x:y.

A semiconductor device including: one or more pieces of first wiring having a main wiring section and a bifurcation wiring section; one or a plurality of pieces of second wiring having a trunk wiring section and a plurality of branch wiring sections within a gap region between the main wiring section and the bifurcation wiring section; one or a plurality of transistors each divided and formed into a plurality of pieces, the plurality of branch wiring sections individually functioning as a gate electrode and the one or plurality of transistors having a source region formed within the main wiring section and within the bifurcation wiring section and having a drain region formed between the plurality of branch wiring sections; and one or a plurality of pieces of third wiring electrically connected to the drain region of the one or plurality of transistors.

A transistor with stable electrical characteristics is provided. The transistor includes a first insulator over a substrate; first to third oxide insulators over the first insulator; a second insulator over the third oxide insulator; a first conductor over the second insulator; and a third insulator over the first conductor. An energy level of a conduction band minimum of each of the first and second oxide insulators is closer to a vacuum level than that of the oxide semiconductor is. An energy level of a conduction band minimum of the third oxide insulator is closer to the vacuum level than that of the second oxide insulator is. The first insulator contains oxygen. The number of oxygen molecules released from the first insulator measured by thermal desorption spectroscopy is greater than or equal to 1E14 molecules/cm.sup.2 and less than or equal to 1E16 molecules/cm.sup.2.

A semiconductor device includes a first insulating layer over a substrate, a first metal oxide layer over the first insulating layer, an oxide semiconductor layer over the first metal oxide layer, a second metal oxide layer over the oxide semiconductor layer, a gate insulating layer over the second metal oxide layer, a second insulating layer over the second metal oxide layer, and a gate electrode layer over the gate insulating layer. The gate insulating layer includes a region in contact with a side surface of the gate electrode layer. The second insulating layer includes a region in contact with the gate insulating layer. The oxide semiconductor layer includes first to third regions. The first region includes a region overlapping with the gate electrode layer. The second region, which is between the first and third regions, includes a region overlapping with the gate insulating layer or the second insulating layer. The second and third regions each include a region containing an element N (N is phosphorus, argon, or xenon).

A thin film transistor array substrate includes a bottom gate disposed on a substrate and a bottom gate insulating layer covering the bottom gate, a semiconductor oxide layer disposed on the bottom gate insulating layer and an etch blocking layer covering the semiconductor oxide layer and including a first via, a drain disposed on the etch blocking layer and contacting with the semiconductor oxide layer through the first via and an insulating protection layer covering the drain, a second via arranged in the insulating protection layer, the etch blocking layer and the bottom gate insulating layer, a top gate disposed on insulating protection layer and contacting with the bottom gate through the second via. A method for manufacturing the thin film transistor array substrate is also disclosed. The thin film transistor prevents the threshold voltage thereof from being drifted in a case of negative bias illumination stress (NBIS).

The present invention provides a semiconductor structure, including a base, a patterned oxide semiconductor (OS) layer, two source/drain regions, a protective layer, a gate layer and a gate dielectric layer. The patterned OS layer is disposed on the base. Two source/drain regions are disposed on the patterned OS layer and are separated by a recess. Each source/drain region includes an inner sidewall facing the recess and an outer sidewall opposite to the inner sidewall. The protective layer is disposed on a sidewall of the patterned OS layer but is not on the inner sidewall of the source/drain region. The gate layer is disposed on the patterned OS layer, and the gate dielectric layer is disposed between the gate layer and the patterned OS layer.

To provide a semiconductor device that includes an oxide semiconductor and is miniaturized while keeping good electrical properties. In the semiconductor device, an oxide semiconductor layer filling a groove is surrounded by insulating layers including an aluminum oxide film containing excess oxygen. Excess oxygen contained in the aluminum oxide film is supplied to the oxide semiconductor layer, in which a channel is formed, by heat treatment in a manufacturing process of the semiconductor device. Moreover, the aluminum oxide film forms a barrier against oxygen and hydrogen, which inhibits the removal of oxygen from the oxide semiconductor layer surrounded by the insulating layers including an aluminum oxide film and the entry of impurities such as hydrogen in the oxide semiconductor layer. Thus, a highly purified intrinsic oxide semiconductor layer can be obtained. The threshold voltage is controlled effectively by gate electrode layers formed over and under the oxide semiconductor layer.

Provided is a semiconductor device which has low power consumption and can operate at high speed. The semiconductor device includes a memory element including a first transistor including crystalline silicon in a channel formation region, a capacitor for storing data of the memory element, and a second transistor which is a switching element for controlling supply, storage, and release of charge in the capacitor. The second transistor is provided over an insulating film covering the first transistor. The first and second transistors have a source electrode or a drain electrode in common.

In a semiconductor device including a transistor, the transistor is provided over a first insulating film, and the transistor includes an oxide semiconductor film over the first insulating film, a gate insulating film over the oxide semiconductor film, a gate electrode over the gate insulating film, a second insulating film over the oxide semiconductor film and the gate electrode, and a source and a drain electrodes electrically connected to the oxide semiconductor film. The first insulating film includes oxygen. The second insulating film includes hydrogen. The oxide semiconductor film includes a first region in contact with the gate insulating film and a second region in contact with the second insulating film. The first insulating film includes a third region overlapping with the first region and a fourth region overlapping with the second region. The impurity element concentration of the fourth region is higher than that of the third region.

A minute transistor is provided. A transistor with low parasitic capacitance is provided. A transistor having high frequency characteristics is provided. A transistor having a high on-state current is provided. A semiconductor device including the transistor is provided. A semiconductor device having a high degree of integration is provided. A semiconductor device including an oxide semiconductor; a second insulator; a second conductor; a third conductor; a fourth conductor; a fifth conductor; a first conductor and a first insulator embedded in an opening portion formed in the second insulator, the second conductor, the third conductor, the fourth conductor, and the fifth conductor; a region where a side surface and a bottom surface of the second conductor are in contact with the fourth conductor; and a region where a side surface and a bottom surface of the third conductor are in contact with the fifth conductor.