A method for making a semiconductor device may include forming a semiconductor layer, and forming a superlattice adjacent the semiconductor layer and including stacked groups of layers. Each group of layers may include stacked base semiconductor monolayers defining a base semiconductor portion, and at least one oxygen monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The at least one oxygen monolayer of a given group of layers may comprise an atomic percentage of .sup.18O greater than 10 percent.

A semiconductor structure includes a metal gate structure (MG) formed over a substrate, a first gate spacer formed on a first sidewall of the MG, a second gate spacer formed on a second sidewall of the MG opposite to the first sidewall, where the second gate spacer is shorter than the first gate spacer, a source/drain (S/D) contact (MD) adjacent to the MG, where a sidewall of the MD is defined by the second gate spacer, and a contact feature configured to electrically connect the MG to the MD.

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.

A semiconductor structure includes a metal gate structure (MG) formed over a substrate, a first gate spacer formed on a first sidewall of the MG, a second gate spacer formed on a second sidewall of the MG opposite to the first sidewall, where the second gate spacer is shorter than the first gate spacer, a source/drain (S/D) contact (MD) adjacent to the MG, where a sidewall of the MD is defined by the second gate spacer, and a contact feature configured to electrically connect the MG to the MD.

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.

A manufacturing method of a semiconductor device at least includes the following steps. A substrate having a stacked structure is provided. An epitaxy process is performed to form an epitaxial layer on the substrate on two sides of the stacked structure. A recess is forming on the two sides of the stacked structure, wherein the recess penetrates through the epitaxial layer, extends into the substrate, and has a tip located in the substrate. A source/drain region is formed in the recess, wherein a material of the source/drain region comprises silicon germanium. A spacer wall material layer is formed on the substrate. A portion of the stacked structure is removed to from a gate structure. A portion of the spacer wall material layer is removed to form a spacer wall on the epitaxial layer. A semiconductor device is also provided.

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 device comprising an active region, and a gate having side portions and a middle portion, whereby the middle portion is arranged between the side portions. The side portions and the middle portion of the gate may be arranged over the active region. The middle portion may be horizontally wider than the side portions. A first gate contact may be arranged over the middle portion.

A method for fabricating a semiconductor device includes the steps of forming a gate structure on a substrate, forming an epitaxial layer adjacent to the gate structure, and then forming a first cap layer on the epitaxial layer. Preferably, a top surface of the first cap layer includes a curve concave upward and a bottom surface of the first cap layer includes a planar surface higher than a top surface of the substrate.

In some aspects, a semiconductor die includes an insulation layer disposed on a substrate, a gate spacer disposed in the insulation layer, a gate disposed between the gate spacer, a first dielectric gate layer disposed on the gate between the gate spacer, a second dielectric gate layer disposed on the first dielectric gate layer between the gate spacer, a gate contact coupled to the gate and in contact with the first dielectric gate layer and the second dielectric gate layer, and a source/drain contact that has a single inner spacer.