A metal gate transistor includes a substrate, a metal gate on the substrate, and a source/drain region in the substrate adjacent to the metal gate. The metal gate includes a high-k dielectric layer, a bottom barrier metal (BBM) layer comprising TiSiN on the high-k dielectric layer, a TiN layer on the BBM layer, a TiAl layer between the BBM layer and the TiN layer, and a low resistance metal layer on the TiN layer.

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.

A semiconductor device is provided. A substrate includes a first region and a second region. A first wire pattern, extending in a first direction, is formed at a first height from the substrate of the first region. A second wire pattern, extending in a second direction, is formed at a second height from the substrate of the second region. The first height is different from the second height. A first gate electrode, surrounding the first wire pattern, extends in a third direction crossing the first direction. A second gate electrode, surrounding the second wire pattern, extends in a fourth direction crossing the second direction. A first gate insulation layer is formed along a circumference of the first wire pattern and a sidewall of the first gate electrode. A second gate insulation layer is formed along a circumference of the second wire pattern and a sidewall of the second gate electrode.

A semiconductor device and methods of fabricating the same are disclosed. The semiconductor device includes a substrate, a fin structure with a fin top surface disposed on the substrate, a source/drain (S/D) region disposed on the fin structure, a gate structure disposed on the fin top surface, and a gate spacer with first and second spacer portions disposed between the gate structure and the S/D region. The first spacer portion extends above the fin top surface and is disposed along a sidewall of the gate structure. The second spacer portion extends below the fin top surface and is disposed along a sidewall of the S/D region.

A semiconductor device with multiple silicide regions is provided. In embodiments a first silicide precursor and a second silicide precursor are deposited on a source/drain region. A first silicide with a first phase is formed, and the second silicide precursor is insoluble within the first phase of the first silicide. The first phase of the first silicide is modified to a second phase of the first silicide, and the second silicide precursor being soluble within the second phase of the first silicide. A second silicide is formed with the second silicide precursor and the second phase of the first silicide.

A semiconductor device includes a semiconductor fin, a gate structure, source/drain structures, and a contact structure. The semiconductor fin extends from a substrate. The gate structure extends across the semiconductor fin. The source/drain structures are on opposite sides of the gate structure. The contact structure is over a first one of the source/drain structures. The contact structure includes a semiconductor contact and a metal contact over the semiconductor contact. The semiconductor contact has a higher dopant concentration than the first one of the source/drain structures. The first one of the source/drain structures includes a first portion and a second portion at opposite sides of the fin and interfacing the semiconductor contact.

A semiconductor device includes source/drain regions, a gate structure, a first gate spacer, and a dielectric material. The source/drain regions are over a substrate. The gate structure is laterally between the source/drain regions. The first gate spacer is on a first sidewall of the gate structure, and spaced apart from a first one of the source/drain regions at least in part by a void region. The dielectric material is between the first one of the source/drain regions and the void region. The dielectric material has a gradient ratio of a first chemical element to a second chemical element.

A semiconductor device includes: a substrate, a gate structure on the substrate, and a spacer adjacent to the gate structure, in which the spacer extends to a top surface of the gate structure, a top surface of the spacer includes a planar surface, the spacer encloses an air gap, and the spacer is composed of a single material. The gate structure includes a high-k dielectric layer, a work function metal layer, and a low resistance metal layer, in which the high-k dielectric layer is U-shaped. The semiconductor device also includes an interlayer dielectric (ILD) layer around the gate structure and a hard mask on the spacer, in which the top surface of the hard mask is even with the top surface of the ILD layer.

A pressure sensor and methods of making a pressure sensor are described. In preferred embodiments, the pressure sensor is designed for low-pressure and high-sensitivity applications. In some embodiments, the pressure sensor comprises: a frame made from a single-crystal silicon starting material, the frame surrounding a cavity; a diaphragm that covers the cavity, the diaphragm constructed from a separate layer of material deposited on the single-crystal silicon starting material; a support structure that spans the diaphragm wherein the support structure is formed from the single-crystal starting material; and, a piezoresistor formed across an intersection of the frame and the support structure.

A method of forming field effect transistors (FETs) and on Integrated Circuit (IC) chips with the FETs. Channel placeholders at FET locations are undercut at each end of FET channels. Source/drain regions adjacent to each channel placeholder extend into and fill the undercut. The channel placeholder is opened to expose channel surface under each channel placeholder. Source/drain extensions are formed under each channel placeholder, adjacent to each source/drain region. After removing the channel placeholders metal gates are formed over each said FET channel.