Occurrence of short-channel characteristics and parasitic capacitance of a MOSFET on a SOI substrate is prevented. A sidewall having a stacked structure obtained by sequentially stacking a silicon oxide film and a nitride film is formed on a side wall of a gate electrode on the SOI substrate. Subsequently, after an epitaxial layer is formed beside the gate electrode, and then, the nitride film is removed. Then, an impurity is implanted into an upper surface of the semiconductor substrate with using the gate electrode and the epitaxial layer as a mask, so that a halo region is formed in only a region of the upper surface of the semiconductor substrate which is right below a vicinity of both ends of the gate electrode.

A more convenient and highly reliable semiconductor device which has a transistor including an oxide semiconductor with higher impact resistance used for a variety of applications is provided. A semiconductor device has a bottom-gate transistor including a gate electrode layer, a gate insulating layer, and an oxide semiconductor layer over a substrate, an insulating layer over the transistor, and a conductive layer over the insulating layer. The insulating layer covers the oxide semiconductor layer and is in contact with the gate insulating layer. In a channel width direction of the oxide semiconductor layer, end portions of the gate insulating layer and the insulating layer are aligned with each other over the gate electrode layer, and the conductive layer covers a channel formation region of the oxide semiconductor layer and the end portions of the gate insulating layer and the insulating layer and is in contact with the gate electrode layer.

The present disclosure relates to the field of display technologies, and in particular to a thin film transistor and a method for manufacturing the same, an array substrate and a display device. An active layer of the thin film transistor includes at least two metal oxide semi-conductor layers, the at least two metal oxide semi-conductor layers include a channel layer and a first protection layer, and metals in the channel layer include at least one of indium, gallium and zinc. Praseodymium is doped into the channel layer. And, in the channel layer, a number density of praseodymium atoms in the channel layer gradually decreases with a distance from the first protection layer.

It is an object to manufacture a highly reliable display device using a thin film transistor having favorable electric characteristics and high reliability as a switching element. In a bottom gate thin film transistor including an amorphous oxide semiconductor, an oxide conductive layer having a crystal region is formed between an oxide semiconductor layer which has been dehydrated or dehydrogenated by heat treatment and each of a source electrode layer and a drain electrode layer which are formed using a metal material. Accordingly, contact resistance between the oxide semiconductor layer and each of the source electrode layer and the drain electrode layer can be reduced; thus, a thin film transistor having favorable electric characteristics and a highly reliable display device using the thin film transistor can be provided.

An object is to improve the drive capability of a semiconductor device. The semiconductor device includes a first transistor and a second transistor. A first terminal of the first transistor is electrically connected to a first wiring. A second terminal of the first transistor is electrically connected to a second wiring. A gate of the second transistor is electrically connected to a third wiring. A first terminal of the second transistor is electrically connected to the third wiring. A second terminal of the second transistor is electrically connected to a gate of the first transistor. A channel region is formed using an oxide semiconductor layer in each of the first transistor and the second transistor. The off-state current of each of the first transistor and the second transistor per channel width of 1 m is 1 aA or less.

A thin film transistor includes an insulating matrix layer including an opening therein, a hydrogen-blocking dielectric barrier layer continuously extending over a bottom surface and sidewalls of the opening and over a top surface of the insulating matrix layer, a gate electrode located within the opening, a stack of a gate dielectric and a semiconducting metal oxide plate overlying the gate electrode and horizontally-extending portions of the hydrogen-blocking dielectric barrier layer that overlie the insulating matrix layer, and a source electrode and a drain electrode contacting a respective portion of a top surface of the semiconducting metal oxide plate.

An object is to stabilize electric characteristics of a semiconductor device including an oxide semiconductor to increase reliability. The semiconductor device includes an insulating film; a first metal oxide film on and in contact with the insulating film; an oxide semiconductor film partly in contact with the first metal oxide film; source and drain electrodes electrically connected to the oxide semiconductor film; a second metal oxide film partly in contact with the oxide semiconductor film; a gate insulating film on and in contact with the second metal oxide film; and a gate electrode over the gate insulating film.

Structures for a field-effect transistor and methods of forming a structure for a field-effect transistor. The structure comprises one or more semiconductor layers, a gate on the one or more semiconductor layers, a source/drain region including a first portion in the one or more semiconductor layers and a second portion in the one or more semiconductor layers, and a defect region in the one or more semiconductor layers. The defect region is disposed adjacent to the first portion of the source/drain region.

An oxide semiconductor stacked film which does not easily cause a variation in electrical characteristics of a transistor and has high stability is provided. Further, a transistor which includes the oxide semiconductor stacked film in its channel formation region and has stable electrical characteristics is provided. An oxide semiconductor stacked film includes a first oxide semiconductor layer, a second oxide semiconductor layer, and a third oxide semiconductor layer which are sequentially stacked and each of which contains indium, gallium, and zinc. The content percentage of indium in the second oxide semiconductor layer is higher than that in the first oxide semiconductor layer and the third oxide semiconductor layer, and the absorption coefficient of the oxide semiconductor stacked film, which is measured by the CPM, is lower than or equal to 310.sup.3/cm in an energy range of 1.5 eV to 2.3 eV.

A semiconductor device (100A) includes a first metal layer (12) including a gate electrode (12g); a gate insulating layer (14) formed on the first metal layer; an oxide semiconductor layer (16) formed on the gate insulating layer; a second metal layer (18) formed on the oxide semiconductor layer; an interlayer insulating layer (22) formed on the second metal layer; and a transparent electrode layer (TE) including a transparent conductive layer (Tc). The oxide semiconductor layer includes a first portion (16a) and a second portion (16b) extending while crossing an edge of the gate electrode. The second metal layer includes a source electrode (18s) and a drain electrode (18d). The interlayer insulating layer does not include an organic insulating layer. The interlayer insulating layer includes a contact hole (22a) formed so as to overlap the second portion and an end of the drain electrode that is closer to the second portion. The transparent conductive layer (Tc) is in contact with the end of the drain electrode and the second portion of the oxide semiconductor layer in the contact hole.