The present invention relates generally to semiconductor devices and more particularly, to a structure and method of forming a contact silicide on a source-drain (S-D) region of a field effect transistor (FET) having extensions by using an undercut etch and a salicide process. A method of forming a contact silicide extension is disclosed. The method may include: forming an undercut region below a dielectric layer and above a source-drain region, the undercut region located directly below a bottom of a contact trench and extending below the dielectric layer to a gate spacer formed on a sidewall of a gate stack; and forming a contact silicide in the undercut region, the contact silicide in direct contact with the source-drain region.

A method to form a semiconductor structure with an active region and a compatible dielectric layer is described. In one embodiment, a semiconductor structure has a dielectric layer comprised of an oxide of a first semiconductor material, wherein a second (and compositionally different) semiconductor material is formed between the dielectric layer and the first semiconductor material. In another embodiment, a portion of the second semiconductor material is replaced with a third semiconductor material in order to impart uniaxial strain to the lattice structure of the second semiconductor material.

One method disclosed herein includes, among other things, forming a line-end protection layer in an opening on an entirety of each opposing, spaced-apart first and second end face surfaces of first and second spaced-apart gate electrode structures, respectively, and forming a sidewall spacer adjacent opposing sidewall surfaces of each of the gate electrode structures but not adjacent the opposing first and second end face surfaces having the line-end protection layer positioned thereon.

A method of controlling the facet height of raised source/drain epi structures using multiple spacers, and the resulting device are provided. Embodiments include providing a gate structure on a SOI layer; forming a first pair of spacers on the SOI layer adjacent to and on opposite sides of the gate structure; forming a second pair of spacers on an upper surface of the first pair of spacers adjacent to and on the opposite sides of the gate structure; and forming a pair of faceted raised source/drain structures on the SOI, each of the faceted source/drain structures faceted at the upper surface of the first pair of spacers, wherein the second pair of spacers is more selective to epitaxial growth than the first pair of spacers.

Embodiments are directed to a method of forming a semiconductor device and resulting structures having self-aligned spacer protection layers. The method includes forming a first sacrificial gate adjacent to a second sacrificial gate on a substrate. A dielectric layer is formed on the substrate and above top surfaces of the first and second sacrificial gates. A self-aligned protection region is formed to cover a first portion of the dielectric layer and a second uncovered portion of the dielectric layer is removed. The first portion of the dielectric layer defines a spacer after the second portion of the dielectric layer is removed.

A strained semiconductor layer is produced from a semiconductor layer extending on an insulating layer. A thermal oxidization is performed on the semiconductor layer across its entire thickness to form two bars extending in a direction of a transistor width. Insulating trenches are formed in a direction of a transistor length. A strain of the strained semiconductor layer is induced in one implementation before the thermal oxidation is performed. Alternatively, the strain is induced after the thermal oxidation is performed. The insulating trenches serve to release a component of the strain extending in the direction of transistor width. A component of the strain extending in the direction of transistor length is maintained. The bars and trenches delimit an active area of the transistor include source, drain and channel regions.

A technique relates to forming a semiconductor device. Sacrificial gates are formed on a channel region of a substrate. Epitaxial layers are grown on source-drain areas between the sacrificial gates. A contact liner and contact material are deposited. The liner and the contact material are removed from above the sacrificial gates. Contact areas are blocked with one or more masking materials and etched. The masking material is removed. The contact material is partially recessed and a nitride liner deposited. An oxide layer is deposited and the sacrificial gate is removed. A metal gate is formed on the channel region and recessed. Insulator material and metal gate material are recessed and a cap is formed over the gate.

A semiconductor device includes first source/drain regions disposed at both sides of a first gate structure and including dopants of a first conductivity type, counter regions being in contact with upper portions of the first source/drain regions and under both end portions of the first gate structure, and first halo regions in contact with bottom surfaces of the first source/drain regions. The counter regions include dopants of a second conductivity type that is different from the first conductivity type. The first halo regions include dopants of the second conductivity type.

A method of making a semiconductor device includes forming a source/drain region on a substrate; disposing a gate stack on the substrate and adjacent to the source/drain region, the gate stack including a gate spacer along a sidewall of the gate stack; disposing an inter-level dielectric (ILD) layer on the source/drain region and the gate stack; removing a portion of the ILD layer on the source/drain region to form a source/drain contact pattern; filling the source/drain contact pattern with a layer of silicon material, the layer of silicon material being in contact with the source/drain region and in contact with the gate spacer; depositing a metallic layer over the first layer of silicon material; and performing a silicidation process to form a source/drain contact including a silicide.

A transistor based on topological insulators is provided. In an embodiment a topological insulator is used to form both the channel as well as the source/drain regions, wherein the channel has a first thickness such that the topological insulator material has properties of a semiconductor material and the source/drain regions have a second thickness such that the topological insulator has properties of a conductive material.