A semiconductor device including: a semiconductor substrate including an active region; a plurality of conductive structures formed over the semiconductor substrate; an isolation layer filling a space between the conductive structures and having an opening that exposes the active region between the conductive structures; a pad formed in a bottom portion of the opening and in contact with the active region; a plug liner formed conformally over a sidewall of the opening and exposing the pad; and a contact plug formed over the pad inside the opening.

A III-N semiconductor channel is formed on a III-N transition layer formed on a (111) or (110) surface of a silicon template structure, such as a fin sidewall. In embodiments, the silicon fin has a width comparable to the III-N epitaxial film thicknesses for a more compliant seeding layer, permitting lower defect density and/or reduced epitaxial film thickness. In embodiments, a transition layer is GaN and the semiconductor channel comprises Indium (In) to increase a conduction band offset from the silicon fin. In other embodiments, the fin is sacrificial and either removed or oxidized, or otherwise converted into a dielectric structure during transistor fabrication. In certain embodiments employing a sacrificial fin, the III-N transition layer and semiconductor channel is substantially pure GaN, permitting a breakdown voltage higher than would be sustainable in the presence of the silicon fin.

Semiconductor structures and methods of forming such structures are disclosed. In an embodiment, the semiconductor structure comprises a substrate, a dielectric layer, and a plurality of gates, including a first gate and a pair of adjacent gates. The method comprises forming gate caps on the adjacent gates, including etching portions of the gate electrodes in the adjacent gates to recess the gate electrodes therein, and forming the caps above the recessed gate electrodes. Conductive metal trenches are formed in the dielectric layer, on the sides of the first gate; and after forming the trenches, a contact is formed over the gate electrode of the first gate and over and on one of the conductive trenches. In embodiments, the contact is a gate contact, and in other embodiments, the contact is a non-gate contact.

A semiconductor device comprises a fin structure disposed over a substrate; a gate structure disposed over part of the fin structure; a source/drain structure, which includes part of the fin structure not covered by the gate structure; an interlayer dielectric layer formed over the fin structure, the gate structure, and the source/drain structure; a contact hole formed in the interlayer dielectric layer; and a contact material disposed in the contact hole. The fin structure extends in a first direction and includes an upper layer, wherein a part of the upper layer is exposed from an isolation insulating layer. The gate structure extends in a second direction perpendicular to the first direction. The contact material includes a silicon phosphide layer and a metal layer.

Transistors and methods of forming the same include forming a fin having an active layer between two sacrificial layers. A dummy gate is formed over the fin. Spacers are formed around the dummy gate. The dummy gate is etched away to form a gap over the fin. Material from the two sacrificial layers is etched away in the gap. A gate stack is formed around the active layer in the gap. Source and drain regions are formed in contact with the active layer.

High voltage three-dimensional devices having dielectric liners and methods of forming high voltage three-dimensional devices having dielectric liners are described. For example, a semiconductor structure includes a first fin active region and a second fin active region disposed above a substrate. A first gate structure is disposed above a top surface of, and along sidewalls of, the first fin active region. The first gate structure includes a first gate dielectric, a first gate electrode, and first spacers. The first gate dielectric is composed of a first dielectric layer disposed on the first fin active region and along sidewalls of the first spacers, and a second, different, dielectric layer disposed on the first dielectric layer and along sidewalls of the first spacers. The semiconductor structure also includes a second gate structure disposed above a top surface of, and along sidewalls of, the second fin active region. The second gate structure includes a second gate dielectric, a second gate electrode, and second spacers. The second gate dielectric is composed of the second dielectric layer disposed on the second fin active region and along sidewalls of the second spacers.

A method of making a vertical transistor includes forming a doped source on a substrate; depositing a sacrificial gate material on the source; forming a trench in the sacrificial gate material to expose the doped source; growing an epitaxial layer within the trench to form a channel region extending from the doped source and through the sacrificial gate material; performing an epitaxial growth process to grow an epitaxial layer on a portion of the channel region to form a drain over the sacrificial gate material; depositing a dielectric material on the drain to form a spacer that protects the epitaxial growth; and removing the sacrificial gate material and replacing the sacrificial gate material with a gate stack that surrounds the channel region between the doped source and the drain.

A highly reliable semiconductor device including an oxide semiconductor is provided by preventing a change in its electrical characteristics. A semiconductor device which includes a first oxide semiconductor layer which is in contact with a source electrode layer and a drain electrode layer and a second oxide semiconductor layer which serves as a main current path (channel) of a transistor is provided. The first oxide semiconductor layer serves as a buffer layer for preventing a constituent element of the source and drain electrode layers from diffusing into the channel. By providing the first oxide semiconductor layer, it is possible to prevent diffusion of the constituent element into an interface between the first oxide semiconductor layer and the second oxide semiconductor layer and into the second oxide semiconductor layer.

An electrostatically formed nanowire transistor, includes a source, a drain, and multiple gates surrounding a doped silicon region. The gates include a top gate, a bottom gate, and side gates. The gates induce a channel in said doped silicon region. The channel has a width which is decreased by negative biasing of the side gates, and a height and vertical position controlled by the top and bottom gates.

A semiconductor device includes a substrate, a first source/drain (S/D) region, a second S/D region, and a semiconductor sheet. The first S/D region is disposed on the substrate. The second S/D region is disposed above the first S/D region. The semiconductor sheet interconnects the first and second S/D regions and includes a plurality of turns. A method for fabricating the semiconductor device is also disclosed.