A method to form self-aligned middle-of-line (MOL) contacts between functional gate structures without the need of lithographic patterning and etching by using raised metal semiconductor alloy regions is provided. Raised metal semiconductor alloy regions are formed by reacting a metal layer with a semiconductor material in raised semiconductor material regions formed on portions of at least one active region of a substrate located between functional gate structures. The metal layer includes a metal capable of forming a metal semiconductor alloy with a large volume expansion such that the resulting metal semiconductor alloy regions can be raised to a same height as that of the functional gate structures. As a result, no lithographic patterning and etching between functional gate structures are needed when forming MOL contacts to these raised metal semiconductor alloy regions.

A method of forming a semiconductor device includes following steps. Firstly, a substrate having a transistor is provided, where the transistor includes a source/drain region. A dielectric layer is formed on the substrate, and a contact plug is formed in the dielectric layer to electrically connect the source/drain region. Next, a mask layer is formed on the dielectric layer, where the mask layer includes a first layer and a second layer stacked thereon. After this a slot-cut pattern is formed on the second layer of the mask layer, and a contact slot pattern is formed on the first layer of the mask layer. Finally, the second layer is removed and a contact opening is formed by using the contact slot pattern on the first layer.

A semiconductor process is described. A silicon-phosphorus (SiP) epitaxial layer is formed serving as a source/drain (S/D) region. A crystalline metal silicide layer is formed directly on the SiP epitaxial layer and thus prevents oxidation of the SiP epitaxial layer. A contact plug is formed over the crystalline metal silicide layer.

A semiconductor device includes a semiconductor substrate having a channel region interposed between a first active region and a second active region, and a gate structure formed on the channel region. A first dual-layer source/drain region is on the first active region and a second dual-layer source/drain region is on the second active region. The first and second dual-layer source/drain regions include stacked layers formed of different semiconductor materials. A first extension region is embedded in the first active region and a second extension region is embedded in the second active region.

A method for fabricating a semiconductor device comprises forming a replacement gate structure on a semiconductor layer of a substrate. The replacement gate structure at least including a polysilicon layer. After forming the replacement gate structure, a gate spacer is formed on the replacement gate structure. Atoms are implanted in an upper portion of the polysilicon layer. The implanting expands the upper portion of the polysilicon layer and a corresponding upper portion of the gate spacer in at least a lateral direction beyond a lower portion of the polysilicon layer and a lower portion of the spacer, respectively. After the atoms have been implanted, the polysilicon layer is removed to form a gate cavity. A metal gate stack is formed within the gate cavity. The metal gate stack includes an upper portion having a width that is greater than a width of a lower portion of the metal gate stack.

Methods of forming a memory device having an array portion including a plurality of array transistors and a periphery region including peripheral circuit transistor structures of the memory device, where an upper surface of the periphery region and an upper surface of the array portion are planar (or nearly planar) after formation of the peripheral circuit transistor structures and a plurality of memory cells (formed over the array transistors). The method includes forming the peripheral circuit transistor structures in the periphery region, forming the plurality of array transistors in the array portion and forming a plurality of memory cells over respective vertical transistors. Structures formed by the method have planar upper surfaces of the periphery and array regions.

Source/drain contact structures that exhibit low contact resistance and improved electromigration properties are provided. After forming a first contact conductor portion comprising a metal having a high resistance to electromigration such as tungsten at a bottom portion of source/drain contact trench to form direct contact with a source/drain region of a field effect transistor, a second contact conductor portion comprising a highly conductive metal such as copper or a copper alloy is formed over the first contact conductor portion.

A method of forming a semiconductor device that includes forming a fin structure from a semiconductor substrate, and forming a gate structure on a channel region portion of the fin structure. A source region and a drain region are formed on a source region portion and a drain region portion of the fin structure on opposing sides of the channel portion of the fin structure. At least one sidewall of the source region portion and the drain region portion of the fin structure is exposed. A metal semiconductor alloy is formed on the at least one sidewall of the source region portion and the drain region portion of the fin structure that is exposed.

A semiconductor device includes a gate disposed over a substrate; a source region and a drain region on opposing sides of the gate; and a pair of trench contacts over and abutting an interfacial layer portion of at least one of the source region and the drain region; wherein the interfacial layer includes boron in an amount in a range from about 510.sup.21 to about 510.sup.22 atoms/cm.sup.2.

A semiconductor device can be reduced in size. The semiconductor device has a first conductivity type p type well layer extending in the X direction of the main surface of a semiconductor substrate; a reference potential wire coupled with the p type well layer, and extending in the X direction; first and second active regions arranged on the opposite sides of the reference potential wire in the Y direction; and a gate electrode layer extending in the Y direction in such a manner as to cross with the first and second active regions. Then, the gate electrode layer has a first gate electrode of a second conductivity type at the crossing part with the first active region, a second gate electrode of the second conductivity type at the crossing part with the second active region, and a non-doped electrode between the first gate electrode and the second gate electrode.