An integrated circuit die includes a silicon substrate. PMOS and NMOS transistors are formed on the silicon substrate. The carrier mobilities of the PMOS and NMOS transistors are increased by introducing tensile stress into the channel regions of the NMOS transistors and compressive stress into the channel regions of the PMOS transistors. Tensile stress is introduced by including a region of SiGe below the channel region of the NMOS transistors. Compressive stress is introduced by including regions of SiGe in the source and drain regions of the PMOS transistors.

Metal-oxide-semiconductor (MOS) transistors with reduced subthreshold conduction, and methods of fabricating the same. Transistor gate structures are fabricated in these transistors of a shape and dimension as to overlap onto the active region from the interface between isolation dielectric structures and the transistor active areas. Minimum channel length conduction is therefore not available at the isolation-to-active interface, but rather the channel length along that interface is substantially lengthened, reducing off-state conduction.

Semiconductor devices and methods for manufacturing the same are provided. An example method may include: forming a sacrificial gate stack on a substrate; forming a gate spacer on sidewalls of the sacrificial gate stack; forming an interlayer dielectric layer on the substrate and planarizing it to expose the sacrificial gate stack; partially etching back the sacrificial gate stack to form an opening; expanding the resultant opening so that the opening is in a shape whose size gradually increases from a side adjacent to the substrate towards an opposite side away from the substrate; and removing a remaining portion of the sacrificial gate stack and forming a gate stack in a space defined by the gate spacer.

Semiconductor devices and methods of forming semiconductor devices are disclosed. In some embodiments, a first trench and a second trench are formed in a substrate, and dopants of a first conductivity type are implanted along sidewalls and a bottom of the first trench and the second trench. The first and second trenches are filled with an insulating material, and a gate dielectric and a gate electrode over the substrate, the gate dielectric and the gate electrode extending over the first trench and the second trench. Source/drain regions are formed in the substrate on opposing sides of the gate dielectric and the gate electrode.

Semiconductor devices and methods of forming the same include forming a first channel region on a first semiconductor region. A second channel region is formed on a second semiconductor region. The second semiconductor region is formed from a semiconductor material that is different from a semiconductor material of the first semiconductor region. A semiconductor cap is formed on one or more of the first and second channel regions. A gate dielectric layer is formed over the nitrogen-containing layer. A gate is formed on the gate dielectric.

Semiconductor devices and methods of forming the same include forming a first channel region on a first semiconductor region. A second channel region is formed on a second semiconductor region. The second semiconductor region is formed from a semiconductor material that is different from a semiconductor material of the first semiconductor region. A semiconductor cap is formed on one or more of the first and second channel regions. A gate dielectric layer is formed over the nitrogen-containing layer. A gate is formed on the gate dielectric.

Techniques for preventing leakage of contact material into air-gap spacers during contact formation. For example, a method comprises forming a contact trench on a semiconductor structure over an air-gap spacer and depositing a liner in the contact trench. The liner deposition material fills a portion of the air-gap spacer pinching off the contact trench to the air-gap spacer.

A well of a first type of conductivity is formed in a semiconductor substrate, and wells of a second type of conductivity are formed in the well of the first type of conductivity at a distance from one another. By an implantation of dopants, a doped region of the second type of conductivity is formed in the well of the first type of conductivity between the wells of the second type of conductivity and at a distance from the wells of the second type of conductivity. Source/drain contacts are applied to the wells of the second type of conductivity, and a gate dielectric and a gate electrode are arranged above regions of the well of the first type of conductivity that are located between the wells of the second type of conductivity and the doped region of the second type of conductivity.

There is provided a field-effect transistor including: a gate electrode; a semiconductor layer having a source region and a drain region with the gate electrode in between; contact plugs provided on the source region and the drain region; first metals stacked on the contact plugs; and a low-dielectric constant region provided in a region between the first metals along an in-plane direction of the semiconductor layer and provided at least in a first region below bottom surfaces of the first metals along a stacking direction.

In some examples, a transistor includes a drain, a channel, and a gate. The channel surrounds the drain and has a channel length to width ratio. The gate is over the channel to provide an active channel region that has an active channel region length to width ratio that is greater than the channel length to width ratio.