A method includes forming a source/drain region in a semiconductor fin; after forming the source/drain region, implanting first impurities into the source/drain region; and after implanting the first impurities, implanting second impurities into the source/drain region. The first impurities have a lower formation enthalpy than the second impurities. The method further includes after implanting the second impurities, annealing the source/drain region.

Embodiments of the present disclosure provide methods for forming merged source/drain features from two or more fin structures. The merged source/drain features according to the present disclosure have a merged portion with an increased height percentage over the overall height of the source/drain feature. The increase height percentage provides an increased landing range for source/drain contact features, therefore, reducing the connection resistance between the source/drain feature and the source/drain contact features. In some embodiments, the emerged source/drain features include one or more voids formed within the merged portion.

A semiconductor device includes a substrate and a transistor. The transistor includes a first channel region overlying the substrate and a source/drain region in contact with the first channel region. The source/drain region has a first surface opposite the substrate and side surfaces extending from the first surface. A silicide layer is disposed on the first surface and the side surfaces of the source/drain region.

A semiconductor structure and a method of forming the same are provided. In an embodiment, a semiconductor structure includes a first plurality of channel members over a backside dielectric layer, a second plurality of channel members over the backside dielectric layer, a silicide feature disposed in the backside dielectric layer, and a source/drain feature disposed over the silicide feature and extending between the first plurality of channel members and the second plurality of channel members. The silicide feature extends through an entire depth of the backside dielectric layer.

A semiconductor device structure and a method for forming a semiconductor device structure are provided. The semiconductor device structure includes a metal gate stack over a substrate and an epitaxial structure over the substrate. The semiconductor device structure also includes a conductive contact electrically connected to the epitaxial structure. A topmost surface of the metal gate stack is vertically disposed between a topmost surface of the conductive contact and a bottommost surface of the conductive contact. The semiconductor device structure further includes a first conductive via electrically connected to the metal gate stack. The topmost surface of the conductive contact is vertically disposed between a topmost surface of the first conductive via and a bottommost surface of the first conductive via. In addition, the semiconductor device structure includes a second conductive via electrically connected to the conductive contact.

In an embodiment, a device includes: a gate electrode; a epitaxial source/drain region adjacent the gate electrode; one or more inter-layer dielectric (ILD) layers over the epitaxial source/drain region; a first source/drain contact extending through the ILD layers, the first source/drain contact connected to the epitaxial source/drain region; a contact spacer surrounding the first source/drain contact; and a void disposed between the contact spacer and the ILD layers.

Embodiments of the present invention are directed to fabrication methods and resulting structures that provide buried contacts in the fin-to-fin space of vertical transport field effect transistors (VFETs) that connect the bottom S/D of the transistors to a buried power rail. In a non-limiting embodiment of the invention, a buried power rail is encapsulated in a buried oxide layer of a first wafer. First and second semiconductor fins are formed on a second wafer. The first wafer to the second wafer and a surface of the buried power rail in a fin-to-fin space is exposed. A buried via is formed on the exposed surface of the buried power rail. The buried via electrically couples the buried power rail to a bottom source or drain region of the first semiconductor fin.

Techniques are disclosed for providing an integrated circuit structure having NMOS transistors including an arsenic-doped interface layer between epitaxially grown source/drain regions and a channel region. The arsenic-doped interface layer may include, for example, arsenic-doped silicon (Si:As) having arsenic concentrations in a range of about 1E20 atoms per cm.sup.3 to about 5E21 atoms per cm.sup.3. The interface layer may have a relatively uniform thickness in a range of about 0.5 nm to full fill where the entire source/drain region is composed of the Si:As. In cases where the arsenic-doped interface layer only partially fills the source/drain regions, another n-type doped semiconductor material can fill remainder (e.g., phosphorus-doped III-V compound or silicon). The use of a layer having a high arsenic concentration can provide improved NMOS performance in the form of abrupt junctions in the source/drain regions and highly conductive source/drain regions with negligible diffusion of arsenic into the channel region.

A nano-FET and a method of forming is provided. In some embodiments, a nano-FET includes an epitaxial source/drain region contacting ends of a first nanostructure and a second nanostructure. The epitaxial source/drain region may include a first semiconductor material layer of a first semiconductor material, such that the first semiconductor material layer includes a first segment contacting the first nanostructure and a second segment contacting the second nanostructure, wherein the first segment is separated from the second segment. A second semiconductor material layer is formed over the first segment and the second segment. The second semiconductor material layer may include a second semiconductor material having a higher concentration of dopants of a first conductivity type than the first semiconductor material layer. The second semiconductor material layer may have a lower concentration percentage of silicon than the first semiconductor material layer.

Integrated circuit devices may include a lower transistor and an upper transistor stacked on a substrate and may include a conductive contact. The upper transistor may include an upper source/drain region that overlaps a lower source/drain region of the lower transistor. The conductive contact may contact a side surface of the upper source/drain region and may overlap a center portion of the lower source/drain region. The side surface of the upper source/drain region may include a protrusion and a recess.