A semiconductor device including a gate electrode disposed on a semiconductor substrate and source/drain regions disposed at both sides of the gate electrode, the source/drain regions being formed by implanting impurities. The source/drain regions include an epitaxial layer formed by epitaxially growing a semiconductor material having a different lattice constant from that of the semiconductor substrate in a recessed position at a side of the gate electrode, and a diffusion layer disposed in a surface layer of the semiconductor substrate.

A semiconductor device and methods of fabricating the same are disclosed. The semiconductor device includes a substrate, a fin structure with a fin top surface disposed on the substrate, a source/drain (S/D) region disposed on the fin structure, a gate structure disposed on the fin top surface, and a gate spacer with first and second spacer portions disposed between the gate structure and the S/D region. The first spacer portion extends above the fin top surface and is disposed along a sidewall of the gate structure. The second spacer portion extends below the fin top surface and is disposed along a sidewall of the S/D region.

The present disclosure provides a semiconductor device that includes channel layers vertically stacked over a substrate, a gate structure engaging the channel layers, a source/drain (S/D) formation assistance region partially embedded in the substrate and under a bottommost one of the channel layers, and an S/D epitaxial feature interfacing both the S/D formation assistance region and lateral ends of the channel layers. The S/D formation assistance region includes a semiconductor seed layer embedded in an isolation layer. The isolation layer separates the semiconductor seed layer from physically contacting the substrate.

A method of fabricating a device includes providing a fin extending from a substrate in a device type region, where the fin includes a plurality of semiconductor channel layers. In some embodiments, the method further includes forming a gate structure over the fin. Thereafter, in some examples, the method includes removing a portion of the plurality of semiconductor channel layers within a source/drain region adjacent to the gate structure to form a trench in the source/drain region. In some cases, the method further includes after forming the trench, depositing an adhesion layer within the source/drain region along a sidewall surface of the trench. In various embodiments, and after depositing the adhesion layer, the method further includes epitaxially growing a continuous first source/drain layer over the adhesion layer along the sidewall surface of the trench.

A method includes forming a gate structure over fins protruding from a semiconductor substrate; forming an isolation region surrounding the fins; depositing a spacer layer over the gate structure and over the fins, wherein the spacer layer fills the regions extending between pairs of adjacent fins; performing a first etch on the spacer layer, wherein after performing the first etch, first remaining portions of the spacer layer that are within inner regions extending between pairs of adjacent fins have a first thickness and second remaining portions of the spacer layer that are not within the inner regions have a second thickness less than the first thickness; and forming an epitaxial source/drain region adjacent the gate structure and extending over the fins, wherein portions of the epitaxial source/drain region within the inner regions are separated from the first remaining portions of the spacer layer.

The present disclosure provides a semiconductor device, including a substrate, a first active region in the substrate, a second active region in the substrate and adjacent to the first active region, an isolation region in the substrate and between the first active region and the second active region, and a dummy gate overlapping with the isolation region, wherein an entire bottom width of the dummy gate is greater than an entire top width of the isolation region.

Semiconductor devices including backside vias with enlarged backside portions and methods of forming the same are disclosed. In an embodiment, a device includes a first transistor structure in a first device layer; a front-side interconnect structure on a front-side of the first device layer; a first dielectric layer on a backside of the first device layer; a first contact extending through the first dielectric layer to a source/drain region of the first transistor structure; and a backside interconnect structure on a backside of the first dielectric layer and the first contact, the first contact including a first portion having first tapered sidewalls and a second portion having second tapered sidewalls, widths of the first tapered sidewalls narrowing in a direction towards the backside interconnect structure, and widths of the second tapered sidewalls widening in a direction towards the backside interconnect structure.

A silicon carbide semiconductor device, comprising: a silicon carbide epitaxial layer, wherein the silicon carbide epitaxial layer comprises a first surface and a second surface that are opposite to each other, the first surface comprises a gate region and a source region located on two sides of the gate region; a first trench, opened at the first surface in the gate region; a first voltage-resistant shielding structure in the silicon carbide epitaxial layer and surrounding a lower part of the first trench; a gate structure in the first trench; a gate metal on a surface of the gate structure; a second voltage-resistant shielding structure, embedded under the first surface in the source portion; a source metal on the first surface in the source region; and a doped well, embedded under the first surface and located between the first trench and the second voltage-resistant shielding structure.

A trench gate power MOSFET, including: a substrate provided with a hexagonal wide bandgap semiconductor of a first conductivity type; an epitaxial layer grown on the substrate and of the first conductivity type; a body region formed on the epitaxial layer and of a second conductivity type; a trench formed in the body region by etching, where a length direction of the trench is parallel to a projection, on the surface of a wafer, of the C axis; a second conductivity-type pillar formed by implanting first ions into a bottom region of the trench along the C axis of the hexagonal wide bandgap semiconductor material, where the bottom region of the trench is located below the trench, and is connected to the bottom of the trench, and the longitudinal depth of the second conductivity-type pillar is at least not less than 50% of the thickness of the epitaxial layer located in the bottom region of the trench; and a trench gate formed by filling the trench with a filler.

Methods of forming a semiconductor device are provided. A method according to the present disclosure includes forming, over a workpiece, a dummy gate stack comprising a first semiconductor material, depositing a first dielectric layer over the dummy gate stack using a first process, implanting the workpiece with a second semiconductor material different from the first semiconductor material, annealing the dummy gate stack after the implanting, and replacing the dummy gate stack with a metal gate stack.