A method of forming matched PFET/NFET spacers with differential widths for SG and EG structures and a method of forming differential width nitride spacers for SG NFET and SG PFET structures and PFET/NFET EG structures and respective resulting devices are provided. Embodiments include providing PFET SG and EG structures and NFET SG and EG structures; forming a first nitride layer over the substrate; forming an oxide liner; forming a second nitride layer on sidewalls of the PFET and NFET EG structures; removing horizontal portions of the first nitride layer and the oxide liner over the PFET SG and EG structures; forming RSD structures on opposite sides of each of the PFET SG and EG structures; removing horizontal portions of the first nitride layer and the oxide liner over the NFET SG and EG structures; and forming RSD structures on opposite sides of each of the NFET SG and EG structures.

Methods and structures for forming highly-doped, ultrathin layers for transistors formed in semiconductor-on-insulator substrates are described. High dopant concentrations may be achieved in ultrathin semiconductor layers to improve device characteristics. Ion implantation at elevated temperatures may mitigate defect formation for stoichiometric dopant concentrations up to about 30%. In-plane stressors may be formed adjacent to channels of transistors formed in ultrathin semiconductor layers.

On a semiconductor substrate having an SOI region and a bulk silicon region formed on its upper surface, epitaxial layers are formed in source and drain regions of a MOSFET formed in the SOI region, and no epitaxial layer is formed in source and drain regions of a MOSFET formed in the bulk silicon region. By covering the end portions of the epitaxial layers with silicon nitride films, even when diffusion layers are formed by implanting ions from above the epitaxial layers, it is possible to prevent the impurity ions from being implanted down to a lower surface of a silicon layer.

A method for fabricating semiconductor device includes the steps of: forming a gate structure on a substrate; forming a first spacer and a second spacer around the gate structure; forming a recess adjacent to two sides of the second spacer; performing a cleaning process to trim the second spacer for forming a void between the first spacer and the substrate; and forming an epitaxial layer in the recess.

Source and drain contacts that provide improved contact resistance and contact interface stability for transistors employing silicon and germanium source and drain materials, related transistor structures, integrated circuits, systems, and methods of fabrication are disclosed. Such source and drain contacts include a contact layer of co-deposited titanium and silicon on the silicon and germanium source and drain. The disclosed source and drain contacts improve transistor performance including switching speed and reliability.

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 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 method for fabricating semiconductor device includes: forming a fin-shaped structure on a substrate, wherein the fin-shaped structure is extending along a first direction; forming a gate layer on the fin-shaped structure; removing part of the gate layer and part of the fin-shaped structure to form a first trench for dividing the fin-shaped structure into a first portion and a second portion, wherein the first trench is extending along a second direction; forming a patterned mask on the gate layer and into the first trench; removing part of the gate layer to form a second trench, wherein the second trench is extending along the first direction; and filling a dielectric layer in the first trench and the second trench.

A semiconductor structure includes a substrate, at least one first gate structure, at least one first spacer, at least one source drain structure, at least one conductor, and at least one protection layer. The first gate structure is present on the substrate. The first spacer is present on at least one sidewall of the first gate structure. The source drain structure is present adjacent to the first spacer. The conductor is electrically connected to the source drain structure. The protection layer is present between the conductor and the first spacer and on a top surface of the first gate structure.

Various embodiments of the present disclosure are directed towards a semiconductor device including a gate electrode over a semiconductor substrate. An epitaxial source/drain layer is disposed on the semiconductor substrate and is laterally adjacent to the gate electrode. The epitaxial source/drain layer comprises a first dopant. A diffusion barrier layer is between the epitaxial source/drain layer and the semiconductor substrate. The diffusion barrier layer comprises a barrier dopant that is different from the first dopant.