The present disclosure provides a semiconductor structure. The semiconductor structure includes a fin active region formed on a semiconductor substrate and spanning between a first sidewall of a first shallow trench isolation (STI) feature and a second sidewall of a second STI feature; an anti-punch through (APT) feature of a first type conductivity; and a channel material layer of the first type conductivity, disposed on the APT feature and having a second doping concentration less than the first doping concentration. The APT feature is formed on the fin active region, spans between the first sidewall and the second sidewall, and has a first doping concentration.

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.

Transistors include multiple stress liners. One or more channel structures are suspended at opposite ends from the plurality of stress liners. The stress liners provide a stress on the one or more channel structures. A gate is formed over and around the one or more channel structures, defining a channel region of the one or more channel structures that is covered by the gate. A source and drain region are formed on opposite sides of the gate.

Transistors and methods of forming the same include forming a fin of alternating layers of a channel material and a sacrificial material. Stress liners are formed in contact with both ends of the fin. The stress liners exert a stress on the fin. The sacrificial material is etched away from the fin, such that the layers of the channel material are suspended between the stress liners. A gate stack is formed over and around the suspended layers of channel material.

The present disclosure provides a semiconductor structure. The semiconductor structure includes a fin active region formed on a semiconductor substrate and spanning between a first sidewall of a first shallow trench isolation (STI) feature and a second sidewall of a second STI feature; an anti-punch through (APT) feature of a first type conductivity; and a channel material layer of the first type conductivity, disposed on the APT feature and having a second doping concentration less than the first doping concentration. The APT feature is formed on the fin active region, spans between the first sidewall and the second sidewall, and has a first doping concentration

A method includes providing a substrate having a mesa, forming a first opening in the mesa, the first opening being surrounded by first inner sidewalls of the mesa exposed by the first opening. The method further includes etching from a first one of the first inner sidewalls of the mesa to form a first vertical recess, the first vertical recess having a wide end and a narrow end, with the narrow end defining a first vertically recessed channel region, and forming a first gate structure over the first vertically recessed channel region.

The method for preventing epitaxial growth in a semiconductor device begins with cutting a set of long fins into a set of fins of a FinFET structure. Each of the set of fins has respective cut faces located at the fin ends of a set of fin ends. A photoresist layer is patterned over the set of fin ends on the set of fins of the FinFET structure. The set of fins are isolated from one another by a first dielectric material. The photoresist is patterned over the set of fin ends so that it differs from the photoresist pattern over other areas of the FinFET structure. A set of dielectric blocks is formed on the set of fin ends using the photoresist pattern. The set of dielectric blocks prevents epitaxial growth at the set of fin ends in a subsequent epitaxial growth step.

A method for fabricating a semiconductor device having a substantially undoped channel region includes performing an ion implantation into a substrate, depositing a first epitaxial layer over the substrate, and depositing a second epitaxial layer over the first epitaxial layer. In various examples, a plurality of fins is formed extending from the substrate. Each of the plurality of fins includes a portion of the ion implanted substrate, a portion of the first epitaxial layer, and a portion of the second epitaxial layer. In some embodiments, the portion of the second epitaxial layer of each of the plurality of fins includes an undoped channel region. In various embodiments, the portion of the first epitaxial layer of each of the plurality of fins is oxidized.

Techniques for dielectric isolation in bulk nanosheet devices are provided. In one aspect, a method of forming a nanosheet device structure with dielectric isolation includes the steps of: optionally implanting at least one dopant into a top portion of a bulk semiconductor wafer, wherein the at least one dopant is configured to increase an oxidation rate of the top portion of the bulk semiconductor wafer; forming a plurality of nanosheets as a stack on the bulk semiconductor wafer; patterning the nanosheets to form one or more nanowire stacks and one or more trenches between the nanowire stacks; forming spacers covering sidewalls of the nanowire stacks; and oxidizing the top portion of the bulk semiconductor wafer through the trenches, wherein the oxidizing step forms a dielectric isolation region in the top portion of the bulk semiconductor wafer. A nanowire FET and method for formation thereof are also provided.

A substrate having a first area and a second area is provided. The substrate is patterned to form trenches in the substrate and semiconductor fins between the trenches, wherein the semiconductor fins comprises first semiconductor fins distributed in the first area and second semiconductor fins distributed in the second area. A first fin cut process is performed in the first area to remove portions of the first semiconductor fins. Insulators are formed in the trenches after the first fin cut process is performed. A second fin cut process is performed in the second area to remove portions of the second semiconductor fins until gaps are formed between the insulators in the second area. A gate stack is formed to partially cover the first semiconductor fins, the second semiconductor fins and the insulators.