An RF MOSFET includes respective pluralities of gate fingers, source fingers, and drain fingers formed on a semiconductor structure. The gate fingers are spaced apart from each other along a first direction, extend in a second, orthogonal direction, and are electrically connected to one another through a gate mandrel. The source fingers are spaced apart from each other along the first direction, extend in the second direction, and are electrically connected to one another through a source mandrel. The drain fingers are spaced apart from each other along the first direction, extend in the second direction, and are electrically connected to one another through a drain mandrel. Adjacent unit cell transistors of the RF MOSFET are separated from one another by a dummy gate and a trench that extends into the semiconductor structure. The semiconductor structure may be a bulk semiconductor wafer, a PD-SOI wafer, or an FD-SOI wafer.

FDSOI device fabrication method is disclosed. The method comprises: disposing a buried oxide layer on the silicon substrate; disposing a SiGe channel on the buried oxide layer, disposing a nitrogen passivation layer on the SiGe channel layer; disposing a metal gate on the nitrogen passivation layer, and attaching sidewalls to sides of the metal gate; and disposing source and drain regions on the nitrogen passivation layer at both sides of the metal gate, wherein the source and drain regions are built in a raised SiGe layer. The stack structure of the SiGe layer and the nitrogen passivation layer forms the gate channel. This stack structure avoids the low stress of the silicon channel in the conventional device. In addition, it prevents the Ge diffusion from the SiGe channel to the gate dielectric in the conventional device. Thereby the invention improves reliability and performance of the device.

Embodiments of the disclosure provide an integrated circuit (IC) structure including a gate structure over a semiconductor layer. The gate structure includes a first portion having a first horizontal width, and a second portion laterally adjacent the first portion and having a second horizontal width less than the first horizontal width. A gate contact is on the first portion of the gate structure and is not on the second portion of the gate structure.

A semiconductor device includes a gate structure on a substrate, a single diffusion break (SDB) structure adjacent to the gate structure, a first spacer adjacent to the gate structure, a second spacer adjacent to the SDB structure, a source/drain region between the first spacer and the second spacer, an interlayer dielectric (ILD) layer around the gate structure and the SDB structure, and a contact plug in the ILD layer and on the source/drain region. Preferably, a top surface of the second spacer is lower than a top surface of the first spacer.

A method includes: forming a gate over a semiconductor substrate; forming doped regions in the semiconductor substrate; depositing a dielectric layer on sidewalls of the gate, the dielectric layer including vertical portions laterally surrounding a sidewall of the gate; depositing a spacer laterally surrounding the dielectric layer, the spacer including a carbon-free portion laterally surrounding the vertical portions of the dielectric layer and a carbon-containing portion laterally surrounding the carbon-free portion; forming source/drain regions in the semiconductor substrate; performing an etching operation to remove the gate and vertical portions of the dielectric layer using the carbon-free portion as an etching stop layer to thereby expose the carbon-free portion and form a recess; and forming a gate dielectric layer and a conductive layer in the recess, wherein the gate dielectric layer extends in at least a portion of an area where the vertical portions of the dielectric layer are etched.

A transistor based on topological insulators is provided. In an embodiment a topological insulator is used to form both the channel as well as the source/drain regions, wherein the channel has a first thickness such that the topological insulator material has properties of a semiconductor material and the source/drain regions have a second thickness such that the topological insulator has properties of a conductive material.

Occurrence of short-channel characteristics and parasitic capacitance of a MOSFET on a SOI substrate is prevented. A sidewall having a stacked structure obtained by sequentially stacking a silicon oxide film and a nitride film is formed on a side wall of a gate electrode on the SOI substrate. Subsequently, after an epitaxial layer is formed beside the gate electrode, and then, the nitride film is removed. Then, an impurity is implanted into an upper surface of the semiconductor substrate with using the gate electrode and the epitaxial layer as a mask, so that a halo region is formed in only a region of the upper surface of the semiconductor substrate which is right below a vicinity of both ends of the gate electrode.

A method includes providing a semiconductor structure having an active region and an isolation structure adjacent to the active region, the active region having source and drain regions sandwiching a channel region for a transistor, the semiconductor structure further having a gate structure over the channel region. The method further includes etching a trench in one of the source and drain regions, wherein the trench exposes a portion of a sidewall of the isolation structure, epitaxially growing a first semiconductor layer in the trench, epitaxially growing a second semiconductor layer over the first semiconductor layer, changing a crystalline facet orientation of a portion of a top surface of the second semiconductor layer by an etching process, and epitaxially growing a third semiconductor layer over the second semiconductor layer after the changing of the crystalline facet orientation.

A field effect transistor includes a source region and a drain region formed within and/or above openings in a dielectric capping mask layer overlying a semiconductor substrate and a gate electrode. A source-side silicide portion and a drain-side silicide portion are self-aligned to the source region and to the drain region, respectively.

A semiconductor structure may include one or more metal gates, one or more channels below the one or more metal gates, a gate dielectric layer separating the one or more metal gates from the one or more channels, and a high-k material embedded in the gate dielectric layer. Both the high-k material and the gate dielectric layer may be in direct contact with the one or more channels. The high-k material may provide threshold voltage variation in the one or more metal gates. The high-k material is a first high-k material or a second high-k material. The semiconductor structure may only include the first high-k material embedded in the gate dielectric layer. The semiconductor structure may only include the second high-k material embedded in the gate dielectric layer. The semiconductor structure may include both the first high-k material and the second high-k material embedded in the gate dielectric layer.