An electrical circuit comprising at least two negative capacitance insulators connected in series, one of the two negative capacitance insulators is biased to generate a negative capacitance. One of the negative capacitance insulators may include an air-gap which is part of a nanoelectromechnical system (NEMS) device and the second negative capacitance insulator includes a ferroelectric material. Both of the negative capacitance insulators may be located between the channel and gate of a field effect transistor. The NEMS device may include a movable electrode, a dielectric and a fixed electrode and arranged so that the movable electrode is attached to at least two points and spaced apart from the dielectric and fixed electrode, and the ferroelectric capacitor is electrically connected to either of the electrodes.

A method includes forming a gate structure on a substrate, forming a seal spacer covering a sidewall of the gate structure, forming a sacrificial spacer covering a sidewall of the seal spacer, forming source/drain regions sandwiching a channel region that is under the gate structure, and depositing a contact etch stop layer covering a sidewall of the sacrificial spacer. The method further includes removing the sacrificial spacer to form a trench, wherein the trench exposes a sidewall of the contact etch stop layer and the sidewall of the seal spacer, and depositing an inter-layer dielectric layer, wherein the inter-layer dielectric layer caps the trench, thereby defining an air gap inside the trench.

A method for manufacturing a semiconductor structure includes forming a first dielectric layer on a gate structure and a source drain structure. A recess is formed at least partially in the first dielectric layer. A protection layer is formed at least on a sidewall of the recess. The recess is deepened to expose the source drain structure. A bottom conductor is formed in the recess and is electrically connected to the source drain structure. The protection layer is removed to form a gap between the bottom conductor and the sidewall of the recess.

Structures for a microfluidic channel and methods of forming a structure for a microfluidic channel. The structure comprises a trench in a semiconductor substrate and a semiconductor layer inside the trench. The trench has an entrance and a sidewall extending from the entrance into the semiconductor substrate. The semiconductor layer has a first portion surrounding a portion of the trench to define a cavity and a second portion positioned to obstruct the entrance to the trench. The second portion of the semiconductor layer is thicker than the first portion of the semiconductor layer.

A method for fabricating a semiconductor structure includes providing a base substrate, including a substrate, a plurality of gate structures formed on the substrate, and a cap layer formed on the plurality of gate structures; removing the cap layer to form a trench on each gate structure; and forming a substitution layer in the trench. The dielectric constant of the substitution layer is smaller than the dielectric constant of the cap layer.

A flash memory device includes a substrate, a plurality of active regions and a plurality of first isolation regions alternately arranged in a first direction and extending in a second direction different from the first direction, a plurality of gate structures on the substrate, the gate structures being spaced apart from each other and extending in the second direction, a gap structure between the gate structures, and a second isolation region filling an upper portion of the gap structure and leaving a first air gap in a lower portion of the gap structure.

A semiconductor device includes a semiconductor substrate and a semiconductor fin on the semiconductor substrate and a fin isolation structure on the semiconductor substrate. The fin isolation structure has an air gap dividing the semiconductor fin into two portions of the semiconductor fin, in which the air gap extends into the semiconductor substrate for a distance. The fin isolation structure includes a dielectric cap layer capping a top of the air gap, in which the dielectric cap layer is spaced apart from a bottom of the air gap.

A semiconductor device that includes a gate structure on a channel region of a semiconductor device. Source and drain regions may be present on opposing sides of the channel region. The semiconductor device may further include a composite gate sidewall spacer present on a sidewall of the gate structure. The composite gate sidewall spacer may include a first composition portion having an air gap encapsulated therein, and a second composition portion that is entirely solid and present atop the first composition portion.

A semiconductor device includes a substrate, a gate structure, a spacer, a mask layer, and at least one void. The gate structure is disposed on the substrate, and the gate structure includes a metal gate electrode. The spacer is disposed on sidewalls of the gate structure, and a topmost surface of the spacer is higher than a topmost surface of the metal gate electrode. The mask layer is disposed on the gate structure. At least one void is disposed in the mask layer and disposed between the metal gate electrode and the spacer.

A method for manufacturing a semiconductor structure includes forming a first dielectric layer on a gate structure and a source drain structure. A recess is formed at least partially in the first dielectric layer. A protection layer is formed at least on a sidewall of the recess. The recess is deepened to expose the source drain structure. A bottom conductor is formed in the recess and is electrically connected to the source drain structure. The protection layer is removed to form a gap between the bottom conductor and the sidewall of the recess.