Semiconductor devices having necked semiconductor bodies and methods of forming semiconductor bodies of varying width are described. For example, a semiconductor device includes a semiconductor body disposed above a substrate. A gate electrode stack is disposed over a portion of the semiconductor body to define a channel region in the semiconductor body under the gate electrode stack. Source and drain regions are defined in the semiconductor body on either side of the gate electrode stack. Sidewall spacers are disposed adjacent to the gate electrode stack and over only a portion of the source and drain regions. The portion of the source and drain regions under the sidewall spacers has a height and a width greater than a height and a width of the channel region of the semiconductor body.

A semiconductor structure, such as a CMOS device, includes a first field effect transistor and a second field effect transistor. The first field effect transistor includes a first composite gate electrode containing a first vertical stack of a p-doped semiconductor gate electrode, a first interfacial dielectric layer, and a first metallic gate electrode. The second field effect transistor includes a second composite gate electrode containing a second vertical stack that includes an n-doped semiconductor gate electrode and a second metallic gate electrode. A second interfacial dielectric layer having a second thickness that is thinner than the first interfacial dielectric layer may, or may not, be present in the second composite gate electrode.

Disclosed are integrated circuit (IC) structures and formation methods. In the methods, a gate with a sacrificial gate cap and a sacrificial gate sidewall spacer is formed on a channel region. The cap and sidewall spacer are removed, creating a cavity with a lower portion between the sidewalls of the gate and adjacent metal plugs and with an upper portion above the lower portion and the gate. A first dielectric layer is deposited, forming an air-gap in the lower portion and lining the upper portion. A second dielectric layer is deposited, filling the upper portion. During formation of a gate contact opening (optionally over an active region), the second dielectric layer is removed and the first dielectric layer is anisotropically etched, thereby exposing the gate and creating a dielectric spacer with a lower air-gap segment and an upper solid segment. Metal deposited into the opening forms the gate contact.

A semiconductor device includes a semiconductor fin arranged on a substrate, a gate stack arranged over a channel region of the fin, and a spacer arranged adjacent to the gate stack. A source/drain region is arranged in the fin the source/drain region having a cavity that exposes a portion of the semiconductor fin. An insulator layer is arranged over a portion of the fin, and a conductive contact material is arranged in the cavity and over portions of the source/drain region.

A nonplanar semiconductor device having a semiconductor body formed on an insulating layer of a substrate. The semiconductor body has a top surface opposite a bottom surface formed on the insulating layer and a pair of laterally opposite sidewalls wherein the distance between the laterally opposite sidewalls at the top surface is greater than at the bottom surface. A gate dielectric layer is formed on the top surface of the semiconductor body and on the sidewalls of the semiconductor body. A gate electrode is formed on the gate dielectric layer on the top surface and sidewalls of the semiconductor body. A pair of source/drain regions are formed in the semiconductor body on opposite sides of the gate electrode.

The semiconductor device including: two fins having rectangular parallelepiped shapes arranged in parallel in X-direction; and a gate electrode arranged thereon via a gate insulating film and extending in Y-direction is configured as follows. First, a drain plug is provided over a drain region located on one side of the gate electrode and extending in Y-direction. Then, two source plugs are provided over a source region located on the other side of the gate electrode and extending in Y-direction. Also, the drain plug is arranged in a displaced manner so that its position in Y-direction may not overlap with the two source plugs. According to such a configuration, the gate-drain capacitance can be made smaller than the gate-source capacitance and a Miller effect-based circuit delay can be suppressed. Further, as compared with capacitance on the drain side, capacitance on the source side increases, thereby improving stability of circuit operation.

The semiconductor device including: two fins having rectangular parallelepiped shapes arranged in parallel in X-direction; and a gate electrode arranged thereon via a gate insulating film and extending in Y-direction is configured as follows. First, a drain plug is provided over a drain region located on one side of the gate electrode and extending in Y-direction. Then, two source plugs are provided over a source region located on the other side of the gate electrode and extending in Y-direction. Also, the drain plug is arranged in a displaced manner so that its position in Y-direction may not overlap with the two source plugs. According to such a configuration, the gate-drain capacitance can be made smaller than the gate-source capacitance and a Miller effect-based circuit delay can be suppressed. Further, as compared with capacitance on the drain side, capacitance on the source side increases, thereby improving stability of circuit operation.

A method of fabricating a vertical field effect transistor comprising that includes forming openings through a spacer material to provide fin structure openings to a first semiconductor material, and forming an inner spacer liner on sidewalls of the fin structure openings. A channel semiconductor material is epitaxially formed on a surface of the first semiconductor material filling at least a portion of the fin structure openings. The spacer material is recessed with an etch that is selective to the inner spacer liner to form a first spacer. The inner spacer liner is removed selectively to the channel semiconductor material. A gate structure on the channel semiconductor material, and a second semiconductor material is formed in contact with the channel semiconductor material.

A source/drain region of a semiconductor device is formed using an epitaxial growth process. In an embodiment a first step comprises forming a bulk region of the source/drain region using a first precursor, a second precursor, and an etching precursor. A second step comprises cleaning the bulk region with the etchant along with introducing a shaping dopant to the bulk region in order to modify the crystalline structure of the exposed surfaces. A third step comprises forming a finishing region of the source/drain region using the first precursor, the second precursor, and the etching precursor.

A source/drain region of a semiconductor device is formed using an epitaxial growth process. In an embodiment a first step comprises forming a bulk region of the source/drain region using a first precursor, a second precursor, and an etching precursor. A second step comprises cleaning the bulk region with the etchant along with introducing a shaping dopant to the bulk region in order to modify the crystalline structure of the exposed surfaces. A third step comprises forming a finishing region of the source/drain region using the first precursor, the second precursor, and the etching precursor.