The present disclosure provides a semiconductor device with an air gap between gate-all-around (GAA) transistors and a method for forming the semiconductor device. The semiconductor device includes a first gate stack and a second gate stack disposed over a semiconductor substrate. At least one of the first gate stack and the second gate stack includes a plurality of gate layers, and the first gate stack and the second gate stack have an air gap therebetween. The semiconductor device also includes a first gate structure and a second gate structure disposed over the first gate stack and the second gate stack, respectively, and a first dielectric layer surrounds lower sidewalls of the first gate structure and lower sidewalls of the second gate structure. A width of the first gate structure is greater than a width of the first plug.

The present disclosure provides a method for forming a semiconductor structure. The method includes the following operations. A metal layer is formed. An adhesion-enhancing layer is formed over the metal layer by a silicide operation. A dielectric stack is formed over the adhesion-enhancing layer. A trench is formed in the dielectric stack by removing a portion of dielectric stack aligning with the metal layer. A barrier layer is formed conforming to the sidewall of the trench. A high-k dielectric layer is formed conforming to the barrier layer. A contact is formed in the trench and be connected to the metal layer.

A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate. Each electrically conductive layer within a subset of the electrically conductive layers includes a respective first metal layer containing an elemental metal and a respective first metal silicide layer containing a metal silicide of the elemental metal. Memory openings vertically extend through the alternating stack. Memory opening fill structures located within the memory openings can include a respective memory film and a respective vertical semiconductor channel.

A for preparing a semiconductor device includes forming a first dielectric layer over a semiconductor substrate, and forming an etch stop layer over the first dielectric layer. The method also includes forming a second dielectric layer over the etch stop layer, and forming a first metal plug penetrating through the second dielectric layer, the etch stop layer and the first dielectric layer. The first metal plug protrudes from the second dielectric layer. The method further includes performing an anisotropic etching process to partially remove the first metal plug such that the first metal plug has a convex top surface, and forming a third dielectric layer covering the second dielectric layer and the convex top surface of the first metal plug. In addition, the method includes forming a second metal plug over the first metal plug.

The present disclosure generally relates to dynamic random access memory (DRAM) devices and to semiconductor fabrication for DRAM devices. Certain embodiments disclosed herein provide an integrated processing system and methods for forming CMOS contact, DRAM array bit line contact (BLC), and storage node structures. The integrated processing system and methods enable deposition of contact and storage node layers with reduced contamination and improved quality, thus reducing leakage current and resistance for the final contact and storage node structures.

A semiconductor device structure includes a first dielectric layer disposed over a semiconductor substrate, and a second dielectric layer disposed over the first dielectric layer. The semiconductor device structure also includes a first conductive plug disposed in the first dielectric layer, and a second conductive plug disposed in the second dielectric layer and directly over the first conductive plug. The semiconductor device structure further includes a silicide portion disposed between the first conductive plug and the second conductive plug.

A semiconductor device and method includes: forming a gate stack over a substrate; growing a source/drain region adjacent the gate stack, the source/drain region being n-type doped Si; growing a semiconductor cap layer over the source/drain region, the semiconductor cap layer having Ge impurities, the source/drain region free of the Ge impurities; depositing a metal layer over the semiconductor cap layer; annealing the metal layer and the semiconductor cap layer to form a silicide layer over the source/drain region, the silicide layer having the Ge impurities; and forming a metal contact electrically coupled to the silicide layer.

Embodiments of the invention are directed to an integrated circuit. A non-limiting example of the integrated circuit includes a transistor formed over a substrate. A dielectric region is formed over the transistor and the substrate. A trench is positioned in the dielectric region and over a S/D region of the transistor. A first liner and a conductive plug are within the trench such that the first liner and the conductive plug are only present within a bottom portion of the trench. A substantially oxygen-free replacement liner and a S/D contact are within the top portion of the trench such that a bottom contact surface of the S/D contact directly couples to a top surface of the conductive plug.

Embodiments described herein generally relate to a sequential hydrogenation and nitridization process for reducing interfacial and bulk O atoms in a conductive structure in a semiconductor device. A hydrogenation and plasma nitridization process is performed on a metal nitride layer in a conductive structure prior to deposition of a second metal layer, thereby reducing interfacial oxygen atoms formed on a surface of the metal nitride and oxygen atoms present in the bulk metal layers of the conductive structure. As a result, adhesion of the second metal layer to the metal nitride layer is improved and the electrical resistance of the contact structure is reduced.

A semiconductor device includes a semiconductor substrate comprising a contact region, a silicide present on the contact region, a dielectric layer present on the semiconductor substrate, the dielectric layer comprising an opening to expose a portion of the contact region, a conductor present in the opening, a barrier layer present between the conductor and the dielectric layer, and a metal layer present between the barrier layer and the dielectric layer, wherein a Si concentration of the silicide is varied along a height of the silicide.