Abstract: A semiconductor device includes a substrate, a first source/drain structure, a vertical channel layer, a gate structure, a second source/drain structure and a body epitaxial layer. The first source/drain structure is over the substrate. The vertical channel layer is over the first source/drain structure. The gate structure is on a first sidewall of the vertical channel layer. The second source/drain structure is over the vertical channel layer. The body epitaxial layer is on a second sidewall of the vertical channel layer. The body epitaxial layer and the vertical channel layer are of opposite conductivity types, and the body epitaxial layer is separated from the gate structure.

Abstract: In a method, a fin structure, in which first semiconductor layers and second semiconductor layers are alternately stacked, is formed. A sacrificial gate structure is formed over the fin structure. The first semiconductor layers are etched at a source/drain region of the fin structure, which is not covered by the sacrificial gate structure, thereby forming a first source/drain space in which the second semiconductor layers are exposed. A dielectric layer is formed at the first source/drain space, thereby covering the exposed second semiconductor layers. The dielectric layer and part of the second semiconductor layers are etched, thereby forming a second source/drain space. A source/drain epitaxial layer is formed in the second source/drain space. At least one of the second semiconductor layers is in contact with the source/drain epitaxial layer, and at least one of the second semiconductor layers is separated from the source/drain epitaxial layer.

Abstract: Semiconductor device structures are provided. The semiconductor device structure includes a number of first semiconductor wires over a semiconductor substrate, and the first semiconductor wires are vertically spaced apart from each other. The semiconductor device structure includes a first gate stack partially wrapping the first semiconductor wires, and a spacer element adjacent to the first gate stack. Each of the first semiconductor wires has a first portion directly below the spacer element and a second portion directly below the first gate stack, the first portion has a first width, the second portion has a second width, and the first width is greater than the second width.

Abstract: A semiconductor device includes channel layers disposed over a substrate, a source/drain region disposed over the substrate, a gate dielectric layer disposed on and wrapping each of the channel layers, and a gate electrode layer disposed on the gate dielectric layer and wrapping each of the channel layers. Each of the channel layers includes a semiconductor wire made of a core region, and one or more shell regions. The core region has an approximately square-shape cross section and a first shell of the one or more shells forms a first shell region of an approximately rhombus-shape cross section around the core region and is connected to an adjacent first shell region corresponding to a neighboring semiconductor wire.

Abstract: A semiconductor structure includes a plurality of first semiconductor layers interleaved with a plurality of second semiconductor layers. The first and second semiconductor layers have different material compositions. A dummy gate stack is formed over an uppermost first semiconductor layer. A first etching process is performed to remove portions of the second semiconductor layer that are not disposed below the dummy gate stack, thereby forming a plurality of voids. The first etching process has an etching selectivity between the first semiconductor layer and the second semiconductor layer. Thereafter, a second etching process is performed to enlarge the voids.

Abstract: A semiconductor device includes channel layers disposed over a substrate, a source/drain region disposed over the substrate, a gate dielectric layer disposed on and wrapping each of the channel layers, and a gate electrode layer disposed on the gate dielectric layer and wrapping each of the channel layers. Each of the channel layers includes a semiconductor wire made of a core region, and one or more shell regions. The core region has an approximately square-shape cross section and a first shell of the one or more shells forms a first shell region of an approximately rhombus-shape cross section around the core region and is connected to an adjacent first shell region corresponding to a neighboring semiconductor wire.

Abstract: In a method, a fin structure, in which first semiconductor layers and second semiconductor layers are alternately stacked, is formed. A sacrificial gate structure is formed over the fin structure. The first semiconductor layers are etched at a source/drain region of the fin structure, which is not covered by the sacrificial gate structure, thereby forming a first source/drain space in which the second semiconductor layers are exposed. A dielectric layer is formed at the first source/drain space, thereby covering the exposed second semiconductor layers. The dielectric layer and part of the second semiconductor layers are etched, thereby forming a second source/drain space. A source/drain epitaxial layer is formed in the second source/drain space. At least one of the second semiconductor layers is in contact with the source/drain epitaxial layer, and at least one of the second semiconductor layers is separated from the source/drain epitaxial layer.

Abstract: A semiconductor structure includes a plurality of first semiconductor layers interleaved with a plurality of second semiconductor layers. The first and second semiconductor layers have different material compositions. A dummy gate stack is formed over an uppermost first semiconductor layer. A first etching process is performed to remove portions of the second semiconductor layer that are not disposed below the dummy gate stack, thereby forming a plurality of voids. The first etching process has an etching selectivity between the first semiconductor layer and the second semiconductor layer. Thereafter, a second etching process is performed to enlarge the voids.

Abstract: In a method, a fin structure, in which first semiconductor layers and second semiconductor layers are alternately stacked, is formed. A sacrificial gate structure is formed over the fin structure. The first semiconductor layers are etched at a source/drain region of the fin structure, which is not covered by the sacrificial gate structure, thereby forming a first source/drain space in which the second semiconductor layers are exposed. A dielectric layer is formed at the first source/drain space, thereby covering the exposed second semiconductor layers. The dielectric layer and part of the second semiconductor layers are etched, thereby forming a second source/drain space. A source/drain epitaxial layer is formed in the second source/drain space. At least one of the second semiconductor layers is in contact with the source/drain epitaxial layer, and at least one of the second semiconductor layers is separated from the source/drain epitaxial layer.

Abstract: Semiconductor device structures are provided. The semiconductor device structure includes first semiconductor wires over a semiconductor substrate. The first semiconductor wires are vertically spaced apart from each other. The semiconductor device structure also includes a gate stack surrounding first portions of the first semiconductor wires, and a spacer element surrounding second portions of the first semiconductor wires. The first portions have a first width and the second portions have a second width. In addition, the semiconductor device structure includes a second semiconductor wire between the second portions. The second semiconductor wire has a third width, and the third width is substantially equal to the second width and greater than the first width.

Abstract: A semiconductor device includes a substrate, a first source/drain structure, a vertical channel layer, a gate structure, a second source/drain structure and a body epitaxial layer. The first source/drain structure is over the substrate. The vertical channel layer is over the first source/drain structure. The gate structure is on a first sidewall of the vertical channel layer. The second source/drain structure is over the vertical channel layer. The body epitaxial layer is on a second sidewall of the vertical channel layer. The body epitaxial layer and the vertical channel layer are of opposite conductivity types, and the body epitaxial layer is separated from the gate structure.

Abstract: A semiconductor structure includes a plurality of first semiconductor layers interleaved with a plurality of second semiconductor layers. The first and second semiconductor layers have different material compositions. A dummy gate stack is formed over an uppermost first semiconductor layer. A first etching process is performed to remove portions of the second semiconductor layer that are not disposed below the dummy gate stack, thereby forming a plurality of voids. The first etching process has an etching selectivity between the first semiconductor layer and the second semiconductor layer. Thereafter, a second etching process is performed to enlarge the voids.

Abstract: Semiconductor device structures are provided. The semiconductor device structure includes a first semiconductor wire over a semiconductor substrate. The first semiconductor wire has a first width and a first thickness. The semiconductor device structure also includes a first gate stack surrounding the first semiconductor wire. The semiconductor device structure further includes a second semiconductor wire over the semiconductor substrate. The first semiconductor wire and the second semiconductor wire include different materials. The second semiconductor wire has a second width and a second thickness. The first width is greater than the second width. The first thickness is less than the second thickness. In addition, the semiconductor device structure includes a second gate stack surrounding the second semiconductor wire.

Abstract: A semiconductor device includes a substrate, a well on the substrate and an FFT on the well. The FET includes a first source/drain, a vertical channel layer, a gate structure, a second source/drain and a body structure. The first source/drain is on the well. The vertical channel layer extends form the first source/drain. The first gate structure surrounds a first portion of sidewalls of the vertical channel layer. The second source/drain is on the vertical channel layer. The body structure is in physical contact with the vertical channel layer. The body structure and the vertical channel layer constitute a bipolar device.

Abstract: A semiconductor device includes channel layers disposed over a substrate, a source/drain region disposed over the substrate, a gate dielectric layer disposed on and wrapping each of the channel layers, and a gate electrode layer disposed on the gate dielectric layer and wrapping each of the channel layers. Each of the channel layers includes a semiconductor wire made of a core region, and one or more shell regions. The core region has an approximately square-shape cross section and a first shell of the one or more shells forms a first shell region of an approximately rhombus-shape cross section around the core region and is connected to an adjacent first shell region corresponding to a neighboring semiconductor wire.

Abstract: In a method, a fin structure, in which first semiconductor layers and second semiconductor layers are alternately stacked, is formed. A sacrificial gate structure is formed over the fin structure. The first semiconductor layers are etched at a source/drain region of the fin structure, which is not covered by the sacrificial gate structure, thereby forming a first source/drain space in which the second semiconductor layers are exposed. A dielectric layer is formed at the first source/drain space, thereby covering the exposed second semiconductor layers. The dielectric layer and part of the second semiconductor layers are etched, thereby forming a second source/drain space. A source/drain epitaxial layer is formed in the second source/drain space. At least one of the second semiconductor layers is in contact with the source/drain epitaxial layer, and at least one of the second semiconductor layers is separated from the source/drain epitaxial layer.

Abstract: Semiconductor device structures are provided. The semiconductor device structure includes a first semiconductor wire over a semiconductor substrate. The first semiconductor wire has a first width and a first thickness. The semiconductor device structure also includes a first gate stack surrounding the first semiconductor wire. The semiconductor device structure further includes a second semiconductor wire over the semiconductor substrate. The first semiconductor wire and the second semiconductor wire include different materials. The second semiconductor wire has a second width and a second thickness. The first width is greater than the second width. The first thickness is less than the second thickness. In addition, the semiconductor device structure includes a second gate stack surrounding the second semiconductor wire.

Abstract: In a method, a fin structure, in which first semiconductor layers and second semiconductor layers are alternately stacked, is formed. A sacrificial gate structure is formed over the fin structure. The first semiconductor layers are etched at a source/drain region of the fin structure, which is not covered by the sacrificial gate structure, thereby forming a first source/drain space in which the second semiconductor layers are exposed. A dielectric layer is formed at the first source/drain space, thereby covering the exposed second semiconductor layers. The dielectric layer and part of the second semiconductor layers are etched, thereby forming a second source/drain space. A source/drain epitaxial layer is formed in the second source/drain space. At least one of the second semiconductor layers is in contact with the source/drain epitaxial layer, and at least one of the second semiconductor layers is separated from the source/drain epitaxial layer.

Abstract: A semiconductor device includes a substrate, a well on the substrate and an FFT on the well. The FET includes a first source/drain, a vertical channel layer, a gate structure, a second source/drain and a body structure. The first source/drain is on the well. The vertical channel layer extends form the first source/drain. The first gate structure surrounds a first portion of sidewalls of the vertical channel layer. The second source/drain is on the vertical channel layer. The body structure is in physical contact with the vertical channel layer. The body structure and the vertical channel layer constitute a bipolar device.

Abstract: A semiconductor structure includes a plurality of first semiconductor layers interleaved with a plurality of second semiconductor layers. The first and second semiconductor layers have different material compositions. A dummy gate stack is formed over an uppermost first semiconductor layer. A first etching process is performed to remove portions of the second semiconductor layer that are not disposed below the dummy gate stack, thereby forming a plurality of voids. The first etching process has an etching selectivity between the first semiconductor layer and the second semiconductor layer. Thereafter, a second etching process is performed to enlarge the voids.