A method comprises forming a first fin including alternating first channel layers and first sacrificial layers and a second fin including alternating second channel layers and second sacrificial layers, forming a capping layer over the first and the second fin, forming a dummy gate stack over the capping layer, forming source/drain (S/D) features in the first and the second fin, removing the dummy gate stack to form a gate trench, removing the first sacrificial layers and the capping layer over the first fin to form first gaps, removing the capping layer over the second fin and portions of the second sacrificial layers to from second gaps, where remaining portions of the second sacrificial layers and the capping layers form a threshold voltage (V.sub.t) modulation layer, and forming a metal gate stack in the gate trench, the first gaps, and the second gaps.

Semiconductor device and the manufacturing method thereof are disclosed. An exemplary semiconductor device comprises a first semiconductor stack and a second semiconductor stack over a substrate, wherein each of the first and second semiconductor stacks includes semiconductor layers stacked up and separated from each other; a dummy spacer between the first and second semiconductor stacks, wherein the dummy spacer contacts a first sidewall of each semiconductor layer of the first and second semiconductor stacks; and a gate structure wrapping a second sidewall, a top surface, and a bottom surface of each semiconductor layer of the first and second semiconductor stacks.

An exemplary method for forming a gate stack of a multigate device includes forming a gate dielectric over a channel layer and forming a gate electrode over the gate dielectric. Forming the gate electrode includes forming a work function layer over the gate dielectric and forming a cap over the work function layer. Forming the cap includes forming a metal nitride layer over the work function layer and forming a silicon-comprising layer over the metal nitride layer. Forming the gate electrode includes forming a fluorine-free tungsten layer over the silicon-comprising layer of the cap without breaking vacuum. Forming the fluorine-free tungsten layer over the silicon-comprising layer includes co-flowing a tungsten-comprising precursor (e.g., WCl.sub.5) and a hydrogen-comprising precursor (e.g., H.sub.2).

The present disclosure provides a semiconductor device and a method of manufacturing a semiconductor device. The semiconductor device includes: a substrate; an insulating layer provided with a plurality of trenches extending in a first direction; a first electrode layer and a second electrode layer, where a spacing region is provided between the first electrode layer and the second electrode layer; a semiconductor layer covering bottom portions and sidewalls of all channel trenches, where the channel trenches are at least a part of trench bodies of the trenches located in the spacing region; a gate dielectric layer covering a surface of the semiconductor layer in the channel trenches on a side away from the bottom portions and the sidewalls of the channel trenches; a gate layer, where at least a part of the channel trenches are fully filled with the gate layer.

A method for forming a semiconductor arrangement comprises forming a first fin in a semiconductor layer. A first gate dielectric layer includes a first high-k material is formed over the first fin. A first sacrificial gate electrode is formed over the first fin. A dielectric layer is formed adjacent the first sacrificial gate electrode and over the first fin. The first sacrificial gate electrode is removed to define a first gate cavity in the dielectric layer. A second gate dielectric layer including a second dielectric material different than the first high-k material is formed over the first gate dielectric layer in the first gate cavity. A first gate electrode is formed in the first gate cavity over the second gate dielectric layer.

In an active matrix display device, electric characteristics of thin film transistors included in a circuit are important, and performance of the display device depends on the electric characteristics. Thus, by using an oxide semiconductor film including In, Ga, and Zn for an inverted staggered thin film transistor, variation in electric characteristics of the thin film transistor can be reduced. Three layers of a gate insulating film, an oxide semiconductor layer and a channel protective layer are successively formed by a sputtering method without being exposed to air. Further, in the oxide semiconductor layer, the thickness of a region overlapping with the channel protective film is larger than that of a region in contact with a conductive film.

In a thin film transistor, an increase in off current or negative shift of the threshold voltage is prevented. In the thin film transistor, a buffer layer is provided between an oxide semiconductor layer and each of a source electrode layer and a drain electrode layer. The buffer layer includes a metal oxide layer which is an insulator or a semiconductor over a middle portion of the oxide semiconductor layer. The metal oxide layer functions as a protective layer for suppressing incorporation of impurities into the oxide semiconductor layer. Therefore, in the thin film transistor, an increase in off current or negative shift of the threshold voltage can be prevented.

A self-aligned transistor including an oxide semiconductor film, which has excellent and stable electrical characteristics, is provided. A semiconductor device is provided with a transistor that includes an oxide semiconductor film, a gate electrode overlapping with part of the oxide semiconductor film, and a gate insulating film between the oxide semiconductor film and the gate electrode. The oxide semiconductor film includes a first region and second regions between which the first region is positioned. The second regions include an impurity element. A side of the gate insulating film has a depressed region. Part of the gate electrode overlaps with parts of the second regions in the oxide semiconductor film.

A method for controlling a MIS structure design in a TFT and a system thereof are disclosed. The method comprises: obtaining dielectric constant of silicon nitride in the MIS structure as designed through calculation; and judging whether the dielectric constant of silicon nitride reaches a set value in a TFT manufacturing procedure, wherein if a negative judgment result is obtained, parameters of the MIS structure are adjusted, so as to enable dielectric constant of silicon nitride in the MIS structure after being adjusted to reach the set value in the TFT manufacturing procedure. A MIS structure design can be effectively controlled, thereby improving performance and stability of TFT-LCD products.

A radiation image-pickup device includes: a plurality of pixels configured to generate signal charge based on radiation; and a field effect transistor used to read out the signal charge from the plurality of pixels. The transistor includes a first silicon oxide film, a semiconductor layer, and a second silicon oxide film laminated in order from a substrate side, the semiconductor layer including an active layer, and a first gate electrode disposed to face the semiconductor layer, with the first or the second silicon oxide film interposed therebetween, and the first or the second silicon oxide film or both include an impurity element.