A method for fabricating a static random access memory (SRAM) includes the steps of: forming a gate structure on a substrate; forming an epitaxial layer adjacent to the gate structure; forming a first interlayer dielectric (ILD) layer around the gate structure; transforming the gate structure into a metal gate; forming a contact hole exposing the epitaxial layer, forming a barrier layer in the contact hole, forming a metal layer on the barrier layer, and then planarizing the metal layer and the barrier layer to form a contact plug. Preferably, a bottom portion of the barrier layer includes a titanium rich portion and a top portion of the barrier layer includes a nitrogen rich portion.

Embodiments disclosed herein include semiconductor devices and methods of forming such semiconductor devices. In an embodiment, a semiconductor device comprises a semiconductor channel, a source region adjacent to the semiconductor channel, and a drain region adjacent to the semiconductor channel. In an embodiment, the source region and the drain region each comprise a trench, a conformal silicide lining the trench, and a binary metallic alloy filling the trench.

A method includes forming a conductive feature through a first dielectric layer, sequentially forming a second dielectric layer and a third dielectric layer over the first dielectric layer, and etching the third dielectric layer to form an opening. A first width of the opening at a top surface of the third dielectric layer is greater than a second width of the opening at a first interface between the third dielectric layer and the second dielectric layer. The method also includes etching the second dielectric layer until the opening extends to the conductive feature, thereby forming an enlarged opening, and forming a metal material in the enlarged opening. A third width of the enlarged opening at the first interface is equal to or less than a fourth width of the enlarged opening at a second interface between the second dielectric layer and the first dielectric layer.

A semiconductor device with different gate structures and a method of fabricating the same are disclosed. The a method includes forming a fin structure on a substrate, forming a thermal oxide layer on top and side surfaces of the fin structure, forming a polysilicon structure on the thermal oxide layer, doping portions of the fin structure uncovered by the polysilicon structure to form doped fin portions, forming a nitride layer on the polysilicon structure and the thermal oxide layer, forming an oxide layer on the nitride layer, doping the nitride layer with halogen ions, forming a source/drain region in the fin structure and adjacent to the polysilicon structure, and replacing the polysilicon structure with a gate structure.

A semiconductor structure includes a gate structure over a substrate. The structure also includes a source/drain epitaxial structure formed on opposite sides of the gate structure. The structure also includes a contact structure formed over the gate structure. The structure also includes a metal layer formed over the contact structure. The structure also includes a cap layer formed over the metal layer. The structure also includes a first etch stop layer including a metal compound formed over the cap layer. The structure also includes a second etch stop layer including nitrogen formed over the first etch stop layer. The structure also includes a via structure that passes through the first etch stop layer and the second etch stop layer. The bottom surface of the cap layer is level with the bottom surface of the first etch stop layer

The present disclosure provides a semiconductor device with improved element performance and reliability. The semiconductor device includes a lower insulating layer, a fin-shaped insulating layer that is on the lower insulating layer and extends in a first direction, a field insulating layer that is on the lower insulating layer and extends in the first direction, a plurality of gate structures that are on the fin-shaped insulating layer and include a gate electrode intersecting the fin-shaped insulating layer, a source/drain region that is on the fin-shaped insulating layer and is between the gate structures, and an active pattern that is on the fin-shaped insulating layer and penetrates the gate electrode and is electrically connected to the source/drain region, where the gate electrode extends in a second direction intersecting the first direction.

A semiconductor device structure is provided. The semiconductor device structure includes a substrate having a first fin structure. The semiconductor device structure includes a first source/drain structure over the first fin structure. The semiconductor device structure includes a first dielectric layer over the first source/drain structure and the substrate. The semiconductor device structure includes a first conductive contact structure in the first dielectric layer and over the first source/drain structure. The semiconductor device structure includes a second dielectric layer over the first dielectric layer and the first conductive contact structure. The semiconductor device structure includes a first conductive via structure passing through the second dielectric layer and connected to the first conductive contact structure. The first conductive via structure has a first substantially strip shape in a top view of the first conductive via structure.

A semiconductor device structure and method for forming the same are provided. The semiconductor device structure includes a first metal layer formed over a substrate and a dielectric layer formed over the first metal layer. The semiconductor device structure further includes an adhesion layer formed in the dielectric layer and over the first metal layer and a second metal layer formed in the dielectric layer. The second metal layer is electrically connected to the first metal layer, and a portion of the adhesion layer is formed between the second metal layer and the dielectric layer. The adhesion layer includes a first portion lining with a top portion of the second metal layer, and the first portion has an extending portion along a vertical direction.

FinFET varactors having low threshold voltages and methods of making the same are disclosed herein. An exemplary FinFET varactor includes a fin and a gate structure disposed over a portion of the fin, such that the gate structure is disposed between a first source/drain feature and a second source/drain feature that include a first type dopant. The portion of the fin includes the first type dopant and a second type dopant. A dopant concentration of the first type dopant and a dopant concentration of the second type dopant vary from an interface between the fin and the gate structure to a first depth in the fin. The dopant concentration of the first type dopant is greater than the dopant concentration of the second type dopant from a second depth to a third depth in the fin, where the second depth and the third depth are less than the first depth.

A method includes forming a bottom source/drain contact plug in a bottom inter-layer dielectric. The bottom source/drain contact plug is electrically coupled to a source/drain region of a transistor. The method further includes forming an inter-layer dielectric overlying the bottom source/drain contact plug. A source/drain contact opening is formed in the inter-layer dielectric, with the bottom source/drain contact plug exposed through the source/drain contact opening. A dielectric spacer layer is formed to have a first portion extending into the source/drain contact opening and a second portion over the inter-layer dielectric. An anisotropic etching is performed on the dielectric spacer layer, and a remaining vertical portion of the dielectric spacer layer forms a source/drain contact spacer. The remaining portion of the source/drain contact opening is filled to form an upper source/drain contact plug.