Abstract: Epitaxial source/drain structures for enhancing performance of multigate devices, such as fin-like field-effect transistors (FETs) or gate-all-around (GAA) FETs, and methods of fabricating the epitaxial source/drain structures, are disclosed herein. An exemplary device includes a dielectric substrate. The device further includes a channel layer, a gate disposed over the channel layer, and an epitaxial source/drain structure disposed adjacent to the channel layer. The channel layer, the gate, and the epitaxial source/drain structure are disposed over the dielectric substrate. The epitaxial source/drain structure includes an inner portion having a first dopant concentration and an outer portion having a second dopant concentration that is less than the first dopant concentration. The inner portion physically contacts the dielectric substrate, and the outer portion is disposed between the inner portion and the channel layer. In some embodiments, the outer portion physically contacts the dielectric substrate.

Abstract: One aspect of the present disclosure pertains to a semiconductor device. The semiconductor device includes a semiconductor substrate and a transistor formed over the semiconductor substrate. The transistor includes a first source/drain (S/D) feature, a second S/D feature, a channel region interposed between the first and second S/D features, and a gate stack engaging the channel region. The semiconductor device includes a first S/D contact landing on a top surface of the first S/D feature, a second S/D contact landing on a top surface of the second S/D feature, and a dielectric plug penetrating through the semiconductor substrate and landing on a bottom surface of the first S/D feature. The dielectric plug spans a width equal to or smaller than a width of the first S/D feature.

Abstract: Semiconductor device and the manufacturing method thereof are disclosed. An exemplary semiconductor device comprises a dielectric layer formed over a power rail; a bottom semiconductor layer formed over the dielectric layer; a backside spacer formed along a sidewall of the bottom semiconductor layer; a conductive feature contacting a sidewall of the dielectric layer and a sidewall of the backside spacer; channel semiconductor layers over the bottom semiconductor layer, wherein the channel semiconductor layers are stacked up and separated from each other; a metal gate structure wrapping each of the channel semiconductor layers; and an epitaxial source/drain (S/D) feature contacting a sidewall of each of the channel semiconductor layers, wherein the epitaxial S/D feature contacts the conductive feature, and the conductive feature contacts the power rail.

Abstract: An interconnect fabrication method is disclosed herein that utilizes a disposable etch stop hard mask over a gate structure during source/drain contact formation and replaces the disposable etch stop hard mask with a dielectric feature (in some embodiments, dielectric layers having a lower dielectric constant than a dielectric constant of dielectric layers of the disposable etch stop hard mask) before gate contact formation. An exemplary device includes a contact etch stop layer (CESL) having a first sidewall CESL portion and a second sidewall CESL portion separated by a spacing and a dielectric feature disposed over a gate structure, where the dielectric feature and the gate structure fill the spacing between the first sidewall CESL portion and the second sidewall CESL portion. The dielectric feature includes a bulk dielectric over a dielectric liner. The dielectric liner separates the bulk dielectric from the gate structure and the CESL.

Abstract: A method according to the present disclosure includes receiving a workpiece that includes a gate structure, a first gate spacer feature, a second gate spacer feature, a gate-top dielectric feature over the gate structure, the first gate spacer feature and the second gate spacer feature, a first source/drain feature over a first source/drain region, a second source/drain feature over a second source/drain region, a first dielectric layer over the first source/drain feature, and a second dielectric layer over the second source/drain feature. The method further includes replacing a top portion of the first dielectric layer with a first hard mask layer, forming a second hard mask layer over the first hard mask layer while the second dielectric layer is exposed, etching the second dielectric layer to form a source/drain contact opening and to expose the second source/drain feature, and forming a source/drain contact over the second source/drain feature.

Abstract: A method includes forming a gate stack, growing a source/drain region on a side of the gate stack through epitaxy, depositing a contact etch stop layer (CESL) over the source/drain region, depositing an inter-layer dielectric over the CESL, etching the inter-layer dielectric and the CESL to form a contact opening, and etching the source/drain region so that the contact opening extends into the source/drain region. The method further includes depositing a metal layer extending into the contact opening. Horizontal portions, vertical portions, and corner portions of the metal layer have a substantially uniform thickness. An annealing process is performed to react the metal layer with the source/drain region to form a source/drain silicide region. The contact opening is filled to form a source/drain contact plug.

Abstract: A semiconductor die and the method of forming the same are provided. The semiconductor die includes a first interconnect structure, a second interconnect structure including a conductive feature, and a device layer between the first interconnect structure and the second interconnect structure. The device layer includes a semiconductor fin, a first gate structure on the semiconductor fin, a source/drain region adjacent the first gate structure, and a shared contact extending through the semiconductor fin to be electrically connected to the source/drain region and the first gate structure. The conductive feature contacts the shared contact.

Abstract: A device includes a gate stack; a gate spacer on a sidewall of the gate stack; a source/drain region adjacent the gate stack; a silicide; and a source/drain contact electrically connected to the source/drain region through the silicide. The silicide includes a conformal first portion in the source/drain region, the conformal first portion comprising a metal and silicon; and a conformal second portion over the conformal first portion, the conformal second portion further disposed on a sidewall of the gate spacer, the conformal second portion comprising the metal, silicon, and nitrogen.

Abstract: A semiconductor structure and a method of forming the same are provided. An exemplary method of forming the semiconductor structure includes receiving a workpiece including a fin structure over a front side of a substrate, recessing a source region of the fin structure to form a source opening, extending the source opening into the substrate to form a plug opening, forming a semiconductor plug in the plug opening, planarizing the substrate to expose the semiconductor plug from a back side of the substrate, performing a first wet etching process to remove a portion of the substrate, performing a pre-amorphous implantation (PAI) process to amorphize a rest portion of the substrate, performing a second wet etching process to remove the amorphized rest portion of the substrate to form a dielectric opening, depositing a dielectric layer in the dielectric opening, and replacing the semiconductor plug with a backside source contact.

Abstract: A semiconductor structure and the manufacturing method thereof are disclosed. An exemplary semiconductor structure includes a first source/drain contact and a second source/drain contact spaced apart by a gate structure, an etch stop layer (ESL) over the first source/drain contact and the second source/drain contact, a conductive feature disposed in the etch stop layer and in direct contact with the first source/drain contact and the second source/drain contact, a dielectric layer over the etch stop layer, and a contact via extending through the dielectric layer and electrically connected to the conductive feature. By providing the conductive feature, a number of metal lines in an interconnect structure of the semiconductor structure may be advantageously reduced.

Abstract: A semiconductor device structure, along with methods of forming such, are described. The semiconductor device structure includes a gate electrode layer disposed over a substrate, a source/drain epitaxial feature disposed over the substrate, a first hard mask layer disposed over the gate electrode layer, and a contact etch stop layer (CESL) disposed over the source/drain epitaxial feature. The structure further includes a first interlayer dielectric (ILD) layer disposed on the CESL and a first treated portion of a second hard mask layer disposed on the CESL and the first ILD layer. A top surface of the first hard mask layer and a top surface of the first treated portion of the second mask layer are substantially coplanar. The structure further includes an etch stop layer disposed on the first hard mask layer and the first treated portion of the second mask layer.

Abstract: A method includes forming a gate stack, growing a source/drain region on a side of the gate stack through epitaxy, depositing a contact etch stop layer (CESL) over the source/drain region, depositing an inter-layer dielectric over the CESL, etching the inter-layer dielectric and the CESL to form a contact opening, and etching the source/drain region so that the contact opening extends into the source/drain region. The method further includes depositing a metal layer extending into the contact opening. Horizontal portions, vertical portions, and corner portions of the metal layer have a substantially uniform thickness. An annealing process is performed to react the metal layer with the source/drain region to form a source/drain silicide region. The contact opening is filled to form a source/drain contact plug.

Abstract: A method according to the present disclosure includes receiving a workpiece that includes a gate structure, a first gate spacer feature, a second gate spacer feature, a gate-top dielectric feature over the gate structure, the first gate spacer feature and the second gate spacer feature, a first source/drain feature over a first source/drain region, a second source/drain feature over a second source/drain region, a first dielectric layer over the first source/drain feature, and a second dielectric layer over the second source/drain feature. The method further includes replacing a top portion of the first dielectric layer with a first hard mask layer, forming a second hard mask layer over the first hard mask layer while the second dielectric layer is exposed, etching the second dielectric layer to form a source/drain contact opening and to expose the second source/drain feature, and forming a source/drain contact over the second source/drain feature.

Abstract: In an embodiment, a device includes: a semiconductor substrate; a first fin extending from the semiconductor substrate; a second fin extending from the semiconductor substrate; an epitaxial source/drain region including: a main layer in the first fin and the second fin, the main layer including a first semiconductor material, the main layer having an upper faceted surface and a lower faceted surface, the upper faceted surface and the lower faceted surface each being raised from respective surfaces of the first fin and the second fin; and a semiconductor contact etch stop layer (CESL) contacting the upper faceted surface and the lower faceted surface of the main layer, the semiconductor CESL including a second semiconductor material, the second semiconductor material being different from the first semiconductor material.

Abstract: The present disclosure provides a method for semiconductor fabrication. The method includes receiving a workpiece having gate structures over channel regions on a substrate and source/drain (S/D) features adjacent to the channel regions. The method then forms tungsten S/D contacts over the S/D features in a first ILD layer by a first selective bottom-up metal growth process. The method forms tungsten S/D vias over the tungsten S/D contacts in a second ILD layer by a second selective bottom-up metal growth process. And after forming the tungsten S/D vias, the method forms tungsten gate vias over the gate structures in the first and the second ILD layer. The forming of the tungsten gate vias includes forming a tungsten seed layer by physical vapor deposition (PVD), and depositing tungsten directly on horizontal and sidewall surfaces of the tungsten seed layer by chemical vapor deposition (CVD).

Abstract: A semiconductor device structure, along with methods of forming such, are described. The semiconductor device structure includes a gate electrode layer disposed over a substrate, a source/drain epitaxial feature disposed over the substrate, a first hard mask layer disposed over the gate electrode layer, and a contact etch stop layer (CESL) disposed over the source/drain epitaxial feature. The structure further includes a first interlayer dielectric (ILD) layer disposed on the CESL and a first treated portion of a second hard mask layer disposed on the CESL and the first ILD layer. A top surface of the first hard mask layer and a top surface of the first treated portion of the second mask layer are substantially coplanar. The structure further includes an etch stop layer disposed on the first hard mask layer and the first treated portion of the second mask layer.

Abstract: A semiconductor device includes a layer having a semiconductive material. The layer includes an outwardly-protruding fin structure. An isolation structure is disposed over the layer but not over the fin structure. A first spacer and a second spacer are each disposed over the isolation structure and on sidewalls of the fin structure. The first spacer is disposed on a first sidewall of the fin structure. The second spacer is disposed on a second sidewall of the fin structure opposite the first sidewall. The second spacer is substantially taller than the first spacer. An epi-layer is grown on the fin structure. The epi-layer protrudes laterally. A lateral protrusion of the epi-layer is asymmetrical with respect to the first side and the second side.

Abstract: An interconnect fabrication method is disclosed herein that utilizes a disposable etch stop hard mask over a gate structure during source/drain contact formation and replaces the disposable etch stop hard mask with a dielectric feature (in some embodiments, dielectric layers having a lower dielectric constant than a dielectric constant of dielectric layers of the disposable etch stop hard mask) before gate contact formation. An exemplary device includes a contact etch stop layer (CESL) having a first sidewall CESL portion and a second sidewall CESL portion separated by a spacing and a dielectric feature disposed over a gate structure, where the dielectric feature and the gate structure fill the spacing between the first sidewall CESL portion and the second sidewall CESL portion. The dielectric feature includes a bulk dielectric over a dielectric liner. The dielectric liner separates the bulk dielectric from the gate structure and the CESL.

Abstract: A semiconductor device structure includes nanostructures formed over a substrate. The structure also includes a gate structure formed over and around the nanostructures. The structure also includes a spacer layer formed over a sidewall of the gate structure over the nanostructures. The structure also includes a source/drain epitaxial structure formed adjacent to the spacer layer. The structure also includes a contact structure formed over the source/drain epitaxial structure with an air spacer formed between the spacer layer and the contact structure.

Abstract: A semiconductor device includes a source/drain component of a transistor. A source/drain contact is disposed over the source/drain component. A source/drain via is disposed over the source/drain contact. The source/drain via contains copper. A first liner at least partially surrounds the source/drain via. A second liner at least partially surrounds the first liner. The first liner and the second liner are disposed between the source/drain contact and the source/drain via. The first liner and the second liner have different material compositions.