A method of fabricating a semiconductor device includes forming a fin in a substrate and depositing a spacer material on the fin. The method includes recessing the spacer material so that a surface of the fin is exposed. The method includes removing a portion of the fin within lateral sidewalls of the spacer material to form a recess, leaving a portion of the fin on the lateral sidewalls. The method further includes depositing a semiconductor material within the recess.

A method of fabricating a semiconductor device includes forming a fin in a substrate and depositing a spacer material on the fin. The method includes recessing the spacer material so that a surface of the fin is exposed. The method includes removing a portion of the fin within lateral sidewalls of the spacer material to form a recess, leaving a portion of the fin on the lateral sidewalls. The method further includes depositing a semiconductor material within the recess.

A method includes depositing a first work-function layer and a second work-function layer in a first device region and a second device region, respectively, and depositing a first fluorine-blocking layer and a second fluorine-blocking layer in the first device region and the second device region, respectively. The first fluorine-blocking layer is over the first work-function layer, and the second fluorine-blocking layer is over the second work-function layer. The method further includes removing the second fluorine-blocking layer, and forming a first metal-filling layer over the first fluorine-blocking layer, and a second metal-filling layer over the second work-function layer.

A device includes a substrate, a buffer layer, a nanowire, a gate structure, and a remnant of a sacrificial layer. The buffer layer is above the substrate. The nanowire is above the buffer layer and includes a pair of source/drain regions and a channel region between the source/drain regions. The gate structure surrounds the channel region. The remnant of the sacrificial layer is between the buffer layer and the nanowire and includes a group III-V semiconductor material.

A method includes forming a dummy gate stack over a semiconductor region, forming a dielectric layer at a same level as the dummy gate stack, removing the dummy gate stack to form an opening in the dielectric layer, filling a metal layer extending into the opening, and etching back the metal layer, with remaining portions of the metal layer having edges lower than a top surface of the dielectric layer. The opening is filled with a conductive material, and the conductive material is over the metal layer. The metal layer and the conductive material in combination form a replacement gate. A source region and a drain region are formed on opposite sides of the replacement gate.

A method of manufacturing a semiconductor device includes providing a semiconductor structure including a substrate, a semiconductor fin on the substrate, and a dummy gate structure on the semiconductor fin. The dummy gate structure includes a dummy gate dielectric layer on the semiconductor fin and a dummy gate on the dummy gate dielectric layer. The method also includes forming an interlayer dielectric layer on the semiconductor substrate, planarizing the interlayer dielectric layer to expose an upper surface of the dummy gate, and performing a first doping implant into the semiconductor fin through the dummy gate to form an anti-puncture region in the semiconductor fin. The anti-puncture region has an upper surface lower than an upper surface of a trench isolation portion surrounding the semiconductor fin to prevent a punch through of a source and drain, reducing a current leakage and parasitic capacitance of the semiconductor device.

A tunable breakdown voltage RF MESFET and/or MOSFET and methods of manufacture are disclosed. The method includes forming a first line and a second line on an underlying gate dielectric material. The second line has a width tuned to a breakdown voltage. The method further includes forming sidewall spacers on sidewalls of the first and second line such that the space between first and second line is pinched-off by the dielectric spacers. The method further includes forming source and drain regions adjacent outer edges of the first line and the second line, and removing at least the second line to form an opening between the sidewall spacers of the second line and to expose the underlying gate dielectric material. The method further includes depositing a layer of material on the underlying gate dielectric material within the opening, and forming contacts to a gate structure and the source and drain regions.

The present disclosure describes an exemplary replacement gate process that forms spacer layers in a gate stack to mitigate time dependent dielectric breakdown (TDDB) failures. For example, the method can include a partially fabricated gate structure with a first recess. A spacer layer is deposited into the first recess and etched with an anisotropic etchback (EB) process to form a second recess that has a smaller aperture than the first recess. A metal fill layer is deposited into the second recess.

Semiconductor devices include a first dielectric layer formed over a source and drain region. A second dielectric layer is formed over the first dielectric layer, the second dielectric layer having a flat, non-recessed top surface. A gate stack passes vertically through the first and second dielectric layers to contact the source and drain regions and an underlying substrate.

A tunable breakdown voltage RF MESFET and/or MOSFET and methods of manufacture are disclosed. The method includes forming a first line and a second line on an underlying gate dielectric material. The second line has a width tuned to a breakdown voltage. The method further includes forming sidewall spacers on sidewalls of the first and second line such that the space between first and second line is pinched-off by the dielectric spacers. The method further includes forming source and drain regions adjacent outer edges of the first line and the second line, and removing at least the second line to form an opening between the sidewall spacers of the second line and to expose the underlying gate dielectric material. The method further includes depositing a layer of material on the underlying gate dielectric material within the opening, and forming contacts to a gate structure and the source and drain regions.