A method is provided for fabricating a buried-channel MOSFET and a surface-channel MOSFET of the same type and different gate electrodes on a same wafer. The method includes providing a semiconductor substrate having a well area and a plurality of shallow trench isolation structures; forming a threshold implantation region doped with impurity ions opposite of that of the well area in the well area for the buried-channel MOSFET; forming a gate structure including a gate dielectric layer and a gate electrode on the semiconductor substrate, wherein the gate electrode of the buried-channel MOSFET is doped with impurity ions with a same type as that of the well area, and the gate electrode of the surface-channel MOSFET is doped with impurity ions with a type opposite of that of the well area; and forming source and drain regions in the semiconductor substrate at both sides of the gate structure.

A semiconductor device includes device isolation layer on a substrate to define an active region, a first gate electrode on the active region extending in a first direction parallel to a top surface of the substrate, a second gate electrode on the device isolation layer and spaced apart from the first gate electrode in the first direction, a gate spacer between the first gate electrode and the second gate electrode, and source/drain regions in the active region at opposite sides of the first gate electrode. The source/drain regions are spaced apart from each other in a second direction that is parallel to the top surface of the substrate and crossing the first direction, and, when viewed in a plan view, the first gate electrode is spaced apart from a boundary between the active region and the device isolation layer.

The present invention provides a semiconductor device and a method of forming the same. The semiconductor device includes a substrate, a first transistor and a second transistor. The first transistor and the second transistor are disposed on the substrate. The first transistor includes a first channel and a first work function layer. The second transistor includes a second channel and a second work function layer, where the first channel and the second channel include different dopants, and the second work function layer and the first work function layer have a same conductive type and different thicknesses.

A method of fabricating a semiconductor device includes forming a gate strip including a dummy electrode and a TiN layer. The method includes removing a first portion of the dummy electrode to form a first opening over a P-active region and an isolation region. The method includes performing an oxygen-containing plasma treatment on a first portion of the TiN layer; and filling the first opening with a first metal material. The method includes removing a second portion of the dummy electrode to form a second opening over an N-active region and the isolation region. The method includes performing a nitrogen-containing plasma treatment on a second portion of the TiN layer; and filling the second opening with a second metal material. The second portion of the TiN layer connects to the first portion of the TiN layer over the isolation region.

A semiconductor device includes a substrate having an active pattern thereon, a gate electrode intersecting the active pattern, and a spacer on a sidewall of the gate electrode. The gate electrode includes a first metal pattern adjacent to the active pattern. The first metal pattern has a first portion parallel to the sidewall and a second portion parallel to the substrate. A top surface of the first portion has a descent in a direction from the spacer towards the second portion.

Selective deposition of a silicon-germanium surface layer on semiconductor surfaces can be employed to provide two types of channel regions for field effect transistors. Anneal of an adjustment oxide material on a stack of a silicon-based gate dielectric and a high dielectric constant (high-k) gate dielectric can be employed to form an interfacial adjustment oxide layer contacting a subset of channel regions. Oxygen deficiency can be induced in portions of the high-k dielectric layer overlying the interfacial adjustment oxide layer by deposition of a first work function metallic material layer and a capping layer and a subsequent anneal. Oxygen deficiency can be selectively removed by physically exposing portions of the high-k dielectric layer. A second work function metallic material layer and a gate conductor layer can be deposited and planarized to form gate electrodes that provide multiple effective work functions.

A manufacturing method of a semiconductor device includes the following steps. A first gate dielectric layer is formed in a first gate trench and a second gate dielectric layer is formed in a second gate trench. A first bottom barrier layer is formed on the first gate dielectric layer and the second gate dielectric layer. A first conductivity type work function layer is formed on the first bottom barrier layer. A first treatment to the first gate dielectric layer and/or a second treatment to the first bottom barrier layer on the first gate dielectric layer are performed before the step of forming the first conductivity type work function layer. The first treatment and the second treatment are used to modify threshold voltages of specific transistors, and thicknesses of work function layers formed subsequently may be modified for increasing the related process window accordingly.

A semiconductor device having metal gate includes a first metal gate structure and a second metal gate structure disposed in a first device region and in a second device region on a substrate respectively. The first metal gate structure includes a gate insulating layer, a first bottom barrier layer, a top barrier layer, and a metal layer disposed on the substrate in order, wherein the top barrier layer is directly in contact with the first bottom barrier layer. The second metal gate structure includes the gate insulating layer, a second bottom barrier layer, the top barrier layer, and the metal layer on the substrate in order, wherein the top barrier layer is directly in contact with the second bottom barrier layer. The first bottom barrier layer and the second bottom barrier layer have different impurity compositions.

A method for fabricating semiconductor device is disclosed. The method includes the steps of: providing a substrate having a high-k dielectric layer thereon; forming a first work function layer on the high-k dielectric layer; and forming a first oxygen-containing layer on the first work function layer.

Some embodiments of the present disclosure provide a semiconductor device. The semiconductor device includes a first transistor configured to include a first threshold voltage level. The first transistor includes a gate structure. The gate structure includes a first component including a first conductive type. A second transistor configures to include a second threshold voltage level different from the first threshold voltage level. The second transistor includes a gate structure. The gate structure includes a second component including the first conductive type. At least one extra component is disposed over the second component. The least one extra component includes a second conductive type opposite to the first conductive type. The first transistor and the second transistor are coupled such that the number of the least one extra component is determined by a desired voltage difference between the first threshold voltage level and the second threshold voltage level.