A thin film transistor may be manufactured by forming a gate electrode in an insulating layer over a substrate, forming a gate dielectric over the gate electrode and the insulating layer, forming an active layer over the gate electrode, and forming a source electrode and a drain electrode contacting a respective portion of a top surface of the active layer. A surface oxygen concentration may be increased in at least one of the gate dielectric and the active layer by introducing oxygen atoms into a surface region of a respective one of the gate dielectric and the active layer.

Devices, and methods of forming such devices, having a material that is semimetal when in bulk but is a semiconductor in the devices are described. An example structure includes a substrate, a first source/drain contact region, a channel structure, a gate dielectric, a gate electrode, and a second source/drain contact region. The substrate has an upper surface. The channel structure is connected to and over the first source/drain contact region, and the channel structure is over the upper surface of the substrate. The channel structure has a sidewall that extends above the first source/drain contact region. The channel structure comprises a bismuth-containing semiconductor material. The gate dielectric is along the sidewall of the channel structure. The gate electrode is along the gate dielectric. The second source/drain contact region is connected to and over the channel structure.

Devices, and methods of forming such devices, having a material that is semimetal when in bulk but is a semiconductor in the devices are described. An example structure includes a substrate, a first source/drain contact region, a channel structure, a gate dielectric, a gate electrode, and a second source/drain contact region. The substrate has an upper surface. The channel structure is connected to and over the first source/drain contact region, and the channel structure is over the upper surface of the substrate. The channel structure has a sidewall that extends above the first source/drain contact region. The channel structure comprises a bismuth-containing semiconductor material. The gate dielectric is along the sidewall of the channel structure. The gate electrode is along the gate dielectric. The second source/drain contact region is connected to and over the channel structure.

Systems and approaches for fabricating an integrated circuit structure including a metal layer formed using a beam of low energy atoms are described. In an example, a system for fabricating an integrated circuit structure includes a sample holder for supporting a 300 mm wafer facing down, the substrate having a feature thereon. The system also includes a source for providing a beam of low energy metal atoms to form a metal layer on the feature of the substrate. The system also includes a source of gas atoms for controlling the texture of the layer

A semiconductor device with favorable reliability is provided. The semiconductor device includes a first oxide, a second oxide over the first oxide, a first insulator over the second oxide, a first conductor over the first insulator, and a second conductor and a third conductor over the second oxide. The second conductor includes a first region and a second region, the third conductor includes a third region and a fourth region, the second region is positioned above the first region, the fourth region is positioned above the third region, and each of the second conductor and the third conductor contains tantalum and nitrogen. The atomic ratio of nitrogen to tantalum in the first region is higher than the atomic ratio of nitrogen to tantalum in the second region, and the atomic ratio of nitrogen to tantalum in the third region is higher than the atomic ratio of nitrogen to tantalum in the fourth region.

A semiconductor device with favorable reliability is provided. The semiconductor device includes a first oxide, a second oxide over the first oxide, a first insulator over the second oxide, a first conductor over the first insulator, and a second conductor and a third conductor over the second oxide. The second conductor includes a first region and a second region, the third conductor includes a third region and a fourth region, the second region is positioned above the first region, the fourth region is positioned above the third region, and each of the second conductor and the third conductor contains tantalum and nitrogen. The atomic ratio of nitrogen to tantalum in the first region is higher than the atomic ratio of nitrogen to tantalum in the second region, and the atomic ratio of nitrogen to tantalum in the third region is higher than the atomic ratio of nitrogen to tantalum in the fourth region.

A semiconductor device with high reliability is provided. The present invention relates to a method for manufacturing a transistor including an oxide semiconductor. A stacked-layer structure of an oxide semiconductor and an insulator functioning as a gate insulator is subjected to microwave-excited plasma treatment, whereby the carrier concentration of the oxide semiconductor is reduced and the barrier property of the gate insulator is improved. In addition, a conductor functioning as an electrode and the insulator functioning as a gate insulator are formed in contact with the oxide semiconductor and then the microwave-excited plasma treatment is performed, whereby a high-resistance region and a low-resistance region can be formed in the oxide semiconductor in a self-aligned manner. Moreover, the microwave-excited plasma treatment is performed under an atmosphere containing oxygen with a high pressure, whereby a transistor having favorable electrical characteristics can be provided.

There is provided a method of manufacturing a semiconductor device that is suitable for forming a one-step tapered groove even when a substrate material is a difficult-to-etch material. The method of manufacturing a semiconductor device includes a metal mask forming step, a dry etching step, and a metal mask removing step. The metal mask formation step forms a tapered metal mask having an opening on the back surface of the substrate. The opening exposes a part in the back surface, and an edge portion of the opening has a forward taper to the back surface. The dry etching step forms a tapered groove on the substrate by performing, from an upper side of the tapered metal mask, dry etching on the edge portion of the opening and the substrate exposed from the opening. The metal mask removing step removes the tapered metal mask.

In a top-gate transistor in which an oxide semiconductor film, a gate insulating film, a gate electrode layer, and a silicon nitride film are stacked in this order and the oxide semiconductor film includes a channel formation region, nitrogen is added to regions of part of the oxide semiconductor film and the regions become low-resistance regions by forming a silicon nitride film over and in contact with the oxide semiconductor film. A source and drain electrode layers are in contact with the low-resistance regions. A region of the oxide semiconductor film, which does not contact the silicon nitride film (that is, a region overlapping with the gate insulating film and the gate electrode layer) becomes the channel formation region.

In a top-gate transistor in which an oxide semiconductor film, a gate insulating film, a gate electrode layer, and a silicon nitride film are stacked in this order and the oxide semiconductor film includes a channel formation region, nitrogen is added to regions of part of the oxide semiconductor film and the regions become low-resistance regions by forming a silicon nitride film over and in contact with the oxide semiconductor film. A source and drain electrode layers are in contact with the low-resistance regions. A region of the oxide semiconductor film, which does not contact the silicon nitride film (that is, a region overlapping with the gate insulating film and the gate electrode layer) becomes the channel formation region.