A vertical FinFET includes a semiconductor fin formed over a semiconductor substrate. A self-aligned first source/drain contact is electrically separated from a second source/drain contact by a spacer layer that is formed over an endwall of the fin. The spacer layer, which comprises a dielectric material, allows the self-aligned first source/drain contact to be located in close proximity to an endwall of the fin and the associated second source/drain contact without risk of an electrical short between the adjacent contacts.

Embodiments of the present invention are directed to low band gap channel semiconductor devices. In an example, a device includes a first semiconductor material formed above a substrate, the first semiconductor material having a first band gap. A gate dielectric layer is on a surface of the first semiconductor material. A gate electrode is on the gate dielectric layer. A pair of source/drain regions is on opposite sides of the gate electrode. A channel is disposed in the first semiconductor material between the pair of source/drain regions and beneath the gate electrode. The pair of source/drain regions includes a second semiconductor material having a second band gap, and a third semiconductor material having a third band gap. The second semiconductor material is between the first semiconductor material and the third semiconductor material, and the second band gap is greater than the first bandgap.

A semiconductor device includes a semiconductor substrate having a gate trench including an upper trench and a lower trench. The upper trench is wider than the lower trench. A gate is embedded in the gate trench. The gate includes an upper portion and a lower portion. A first gate dielectric layer is between the upper portion and a sidewall of the upper trench. The first gate dielectric layer has a first thickness. A second gate dielectric layer is between the lower portion and a sidewall of the lower trench and between the lower portion and a bottom surface of the lower trench. The second gate dielectric layer has a second thickness that is smaller than the first thickness.

Gate contact structures disposed over active portions of gates and methods of forming such gate contact structures are described. For example, a semiconductor structure includes a substrate having an active region and an isolation region. A gate structure has a portion disposed above the active region and a portion disposed above the isolation region of the substrate. Source and drain regions are disposed in the active region of the substrate, on either side of the portion of the gate structure disposed above the active region. A gate contact structure is disposed on the portion of the gate structure disposed above the active region of the substrate.

Techniques for forming self-aligned contacts by forming gate sidewall spacers and gates before forming the contacts are provided. In one aspect, a method of forming self-aligned contacts includes the steps of: forming multiple gate sidewall spacers on a substrate; burying the gate sidewall spacers in a dielectric; forming gate trenches by selectively removing the dielectric from regions between the gate sidewall spacers in which gates will be formed; forming the gates in the gate trenches; forming contact trenches by selectively removing the dielectric from regions between the gate sidewall spacers in which the self-aligned contacts will be formed; and forming the self-aligned contacts in the contact trenches. A device structure having self-aligned contacts is also provided.

Techniques for forming self-aligned contacts by forming gate sidewall spacers and gates before forming the contacts are provided. In one aspect, a method of forming self-aligned contacts includes the steps of: forming multiple gate sidewall spacers on a substrate; burying the gate sidewall spacers in a dielectric; forming gate trenches by selectively removing the dielectric from regions between the gate sidewall spacers in which gates will be formed; forming the gates in the gate trenches; forming contact trenches by selectively removing the dielectric from regions between the gate sidewall spacers in which the self-aligned contacts will be formed; and forming the self-aligned contacts in the contact trenches. A device structure having self-aligned contacts is also provided.

A method for forming a semiconductor structure includes forming a strained silicon germanium layer on top of a substrate. At least one patterned hard mask layer is formed on and in contact with at least a first portion of the strained silicon germanium layer. At least a first exposed portion and a second exposed portion of the strained silicon germanium layer are oxidized. The oxidizing process forms a first oxide region and a second oxide region within the first and second exposed portions, respectively, of the strained silicon germanium.

There is set forth herein a semiconductor device fabricated on a bulk wafer having a local buried oxide region underneath a channel region of a MOSFET. In one embodiment the local buried oxide region can be self-aligned to a gate, and a source/drain region can be formed in a bulk substrate. A local buried oxide region can be formed in a semiconductor device by implantation of oxygen into a bulk region of the semiconductor device followed by annealing.

A semiconductor structure includes a source drain region of a first material and an extension region of a second material. A semiconductor device fabrication process includes forming a sacrificial dielectric portion upon a semiconductor substrate, forming a sacrificial gate stack upon the sacrificial dielectric portion, forming a gate spacer upon the sacrificial dielectric portion against the sacrificial gate, forming a source drain region of a first doped material upon the semiconductor substrate against the gate spacer, forming a replacement gate trench by removing the sacrificial gate stack, forming an extension trench by removing the sacrificial dielectric portion, and forming an extension region of a second doped material within the extension trench.

A method includes forming a dummy gate stack, forming a dielectric layer, with the dummy gate stack located in the dielectric layer, removing the dummy gate stack to form a opening in the dielectric layer, forming a metal layer extending into the opening, and etching back the metal layer. The remaining portions of the metal layer in the opening have edges lower than a top surface of the dielectric layer. A conductive layer is selectively deposited in the opening. The conductive layer is over the metal layer, and the metal layer and the conductive layer in combination form a replacement gate.