A transistor includes a bulk semiconductor substrate, and a first source/drain region in the bulk semiconductor substrate separated from a second source/drain region in the bulk semiconductor substrate by a channel region. A first air gap is defined in the bulk semiconductor substrate under the first source/drain region, and a second air gap is defined in the bulk semiconductor substrate under the second source/drain region. A gate is over the channel region. A spacing between the first air gap and the second air gap is greater than or equal to a length of the channel region such that the first and second air gaps are not under the channel region. The air gaps may have a rectangular cross-sectional shape. The air gaps reduce off capacitance of the bulk semiconductor structure to near semiconductor-on-insulator levels without the disadvantages of an air gap under the channel region.

A semiconductor device may include a semiconductor substrate, and shallow trench isolation (STI) regions in the semiconductor substrate defining an active region therebetween in the semiconductor substrate, with the active region having rounded shoulders adjacent the STI regions with an interior angle of at least 125°. The semiconductor device may further include a superlattice on the active region including stacked groups of layers, with each group of layers including stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The semiconductor device may also include a semiconductor circuit on the substrate including the superlattice.

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 includes a semiconductor substrate, a first gate oxide layer, and a first source/drain doped region. The first gate oxide layer is disposed on the semiconductor substrate, and the first gate oxide layer includes a main portion and an edge portion having a sloping sidewall. The first source/drain doped region is disposed in the semiconductor substrate and located adjacent to the edge portion of the first gate oxide layer. The first source/drain doped region includes a first portion and a second portion. The first portion is disposed under the edge portion of the first gate oxide layer in a vertical direction, and the second portion is connected with the first portion.

The performance of a transistor is improved. The semiconductor device according to the embodiment includes: an insulating film (12) that separates an n-type transistor formation region (Tr1) and a p-type transistor formation region (Tr2) from each other, in which each of the n-type transistor formation region and the p-type transistor formation region includes a gate electrode (13) formed in a first direction on a semiconductor substrate (11), and source/drain regions (22) formed on both sides of the gate electrode in a second direction different from the first direction, and a distance from an interface between the insulating film and the source/drain regions to an end of the gate electrode in the second direction is different between the n-type transistor formation region and the p-type transistor formation region.

A method of fabricating a metal gate transistor includes providing a substrate. An interlayer dielectric layer covers the substrate. A dummy gate is embedded in the interlayer dielectric layer. A high-k dielectric layer is disposed between the dummy gate and the substrate. Later, the dummy gate is removed to form a trench, and the high-k dielectric layer is exposed through the trench. After the dummy gate is removed, an ion implantation process is performed to implant fluoride ions into the high-k dielectric layer. Finally, after the ion implantation process, a metal gate is formed to fill in the trench.

A semiconductor device includes a semiconductor substrate, a first gate oxide layer, and a first source/drain doped region. The first gate oxide layer is disposed on the semiconductor substrate, and the first gate oxide layer includes a main portion and an edge portion having a sloping sidewall. The first source/drain doped region is disposed in the semiconductor substrate and located adjacent to the edge portion of the first gate oxide layer. The first source/drain doped region includes a first portion and a second portion. The first portion is disposed under the edge portion of the first gate oxide layer in a vertical direction, and the second portion is connected with the first portion.

A semiconductor device includes a channel pattern including first and second semiconductor patterns stacked on a substrate, a gate electrode covering top and lateral surfaces of the channel pattern and extending in a first direction, and including a first gate segment between the first semiconductor pattern and the second semiconductor pattern, a gate spacer covering a lateral surface of the gate electrode and including an opening exposing the channel pattern, and a first source/drain pattern on a side of the gate spacer and in contact with the channel pattern through the opening, the first source/drain pattern including a sidewall center thickness at a height of the first gate segment and at a center of the opening, and a sidewall edge thickness at the height of the first gate segment and at an edge of the opening, the sidewall edge thickness being about 0.7 to 1 times the sidewall center thickness.

The present application discloses a semiconductor device with a contact having tapered profile and a method for fabricating the semiconductor device. The semiconductor device includes a substrate having a first region and a second region; a first gate structure positioned on the first region; and a second gate structure positioned on the second region; a first contact including a first lower portion positioned on a top surface of the first gate structure, and a first upper portion positioned on the first lower portion; and a second contact including a second lower portion positioned on a top surface of the second gate structure and a sidewall of the second gate structure, and a second upper portion positioned on the second lower portion. Sidewalls of the first lower portion are tapered and sidewalls of the second lower portion are substantially vertical.

A semiconductor structure and method of manufacture and, more particularly, a field effect transistor that has a body contact and method of manufacturing the same is provided. The structure includes a device having a raised source region of a first conductivity type and an active region below the raised source region extending to a body of the device. The active region has a second conductivity type different than the first conductivity type. A contact region is in electric contact with the active region. The method includes forming a raised source region over an active region of a device and forming a contact region of a same conductivity type as the active region, wherein the active region forms a contact body between the contact region and a body of the device.