Abstract: Semiconductor devices having improved source/drain features and methods for fabricating such are disclosed herein. An exemplary device includes a semiconductor layer stack disposed over a mesa structure of a substrate. The device further includes a metal gate disposed over the semiconductor layer stack and an inner spacer disposed on the mesa structure of the substrate. The device further includes a first epitaxial source/drain feature and a second epitaxial source/drain feature where the semiconductor layer stack is disposed between the first epitaxial source/drain feature and the second epitaxial source/drain feature. The device further includes a void disposed between the inner spacer and the first epitaxial source/drain feature.

Abstract: A method for forming a semiconductor device structure includes forming nanostructures over a substrate. The method also includes forming a gate structure wrapped around the nanostructures. The method also includes forming source/drain epitaxial structures over opposite sides of the nanostructures. The method also includes forming a first interlayer dielectric structure over the source/drain epitaxial structures. The method also includes removing the first interlayer dielectric structure. The method also includes forming a recess in the source/drain epitaxial structures. The method also includes forming a silicide structure in the recess. The method also includes forming a second interlayer dielectric structure over the silicide structure.

Abstract: A method for forming a semiconductor device structure is provided. The method includes providing a substrate having a base and a fin over the base. The method includes forming a first gate stack wrapped around the fin. The method includes forming a first gate spacer over a first sidewall of the first gate stack. The method includes partially removing the fin, which is not covered by the first gate stack and the first gate spacer. The method includes removing a first upper portion of the first gate stack to expose a second upper portion of the first gate spacer. The method includes removing the second upper portion of the first gate spacer. The method includes removing a first lower portion of the first gate stack and the fin originally wrapped by the first gate stack. The method includes forming a dielectric channel-cut structure in the trench.

Abstract: A semiconductor device includes a semiconductor substrate, a plurality of metal portions, a plurality of nanosheet structures, and a plurality of isolation structures. The metal portions are disposed on the semiconductor substrate and are spaced apart from each other. The nanosheet structures are surrounded by the metal portions such that the nanosheet structures are spaced apart from each other. The isolation structures are disposed on the semiconductor substrate such that two adjacent ones of the metal portions are isolated from each other by a corresponding one of the isolation structures. Each of the isolation structures includes a first dielectric layer and an air gap surrounded by the first dielectric layer.

Abstract: A semiconductor structure includes substrate, semiconductor layers, source/drain features, metal oxide layers, and a gate structure. The semiconductor layers extend in an X-direction and over the substrate. The semiconductor layers are spaced apart from each other in a Z-direction. The source/drain features are on opposite sides of the semiconductor layers in the X-direction. The metal oxide layers cover bottom surfaces of the semiconductor layers. The gate structure wraps around the semiconductor layers and the metal oxide layers. The metal oxide layers are in contact with the gate structure.

Abstract: A gate oxide formation process includes the following steps. A first gate oxide layer is formed on a substrate. The first gate oxide layer is thinned to a first predetermined thickness. The first gate oxide layer is then thickened to a second predetermined thickness, to thereby form a second gate oxide layer.

Abstract: A method for fabricating a semiconductor device is described. A gate layer, a C-doped first protective layer and a hard mask layer are formed on a substrate and then patterned to form a first stack in a first area and a second stack in a second area. A second protective layer is formed on the sidewalls of the first and the second stacks. A blocking layer is formed in the first area and a first spacer formed on the sidewall of the second protective layers on the sidewall of the second stack in the second area. A semiconductor compound is formed in the substrate beside the first spacer. The blocking layer and the first spacer are removed. The hard mask layer in the first stack and the second stack is removed.

Abstract: A semiconductor process is provided. The prior steps include: a first gate including a first cap layer and a second gate including a second cap layer are formed on a substrate. A hard mask layer is formed to cover the first gate and the second gate. The material of the hard mask layer is different from the material of the first cap layer and the second cap layer. The hard mask layer is removed entirely after a lithography process and an etching process are performed. The following steps include: a material is formed to entirely cover the first gate and the second gate. The material, the first gate and the second gate are etched back to make the first gate and the second gate have the same level and expose layers in both of them.

Abstract: A method for fabricating a semiconductor device is described. A gate layer, a C-doped first protective layer and a hard mask layer are formed on a substrate and then patterned to form a first stack in a first area and a second stack in a second area. A second protective layer is formed on the sidewalls of the first and the second stacks. A blocking layer is formed in the first area and a first spacer formed on the sidewall of the second protective layers on the sidewall of the second stack in the second area. A semiconductor compound is formed in the substrate beside the first spacer. The blocking layer and the first spacer are removed. The hard mask layer in the first stack and the second stack is removed.

Abstract: A semiconductor process is provided. The prior steps include: a first gate including a first cap layer and a second gate including a second cap layer are formed on a substrate. A hard mask layer is formed to cover the first gate and the second gate. The material of the hard mask layer is different from the material of the first cap layer and the second cap layer. The hard mask layer is removed entirely after a lithography process and an etching process are performed. The following steps include: a material is formed to entirely cover the first gate and the second gate. The material, the first gate and the second gate are etched back to make the first gate and the second gate have the same level and expose layers in both of them.