Abstract: The present disclosure describes a semiconductor device includes a substrate, a buffer layer on the substrate, and a stacked fin structure on the buffer layer. The buffer layer can include germanium, and the stacked fin structure can include a semiconductor layer with germanium and tin. The semiconductor device further includes a gate structure wrapped around a portion of the semiconductor layer and an epitaxial structure on the buffer layer and in contact with the semiconductor layer. The epitaxial structure includes germanium and tin.

Abstract: A method includes forming a first semiconductor layer over a substrate; forming a second semiconductor layer over the first semiconductor layer; forming a dummy gate structure over the second semiconductor layer; performing an etching process to form a recess in the first and second semiconductor layers; forming a epitaxy structure over in the recess, wherein the epitaxy structure is in contact with the first and second semiconductor layers; performing a solid phase diffusion process to form a doped region in the epitaxy structure, in which the doped region is in contact with the second semiconductor layer and is separated from the first semiconductor layer; and replacing the dummy gate structure with a metal gate structure.

Abstract: A device comprises a plurality of nanosheets, source/drain stressors, and a gate structure wrapping around the nanosheets. The nanosheets extend in a first direction above a semiconductor substrate and are arranged in a second direction substantially perpendicular to the first direction. The source/drain stressors are on either side of the nanosheets. Each of the source/drain stressors comprises a first epitaxial layer and a second epitaxial layer over the first epitaxial layer. The first and second epitaxial layers are made of a Group IV element and a Group V element. An atomic ratio of the Group V element to the Group IV element in the second epitaxial layer is greater than an atomic ratio of the Group V element to the Group IV element in the first epitaxial layer.

Abstract: A semiconductor device includes a substrate, a gate stack, and epitaxy structures. The substrate has a P-type region. The gate stack is over the P-type region of the substrate and includes a gate dielectric layer, a bottom work function (WF) metal layer, a top WF metal layer, and a filling metal. The bottom WF metal layer is over the gate dielectric layer. The top WF metal layer is over and in contact with the bottom WF metal layer. Dipoles are formed between the top WF metal layer and the bottom WF metal layer, and the dipoles direct from the bottom WF metal layer to the top WF metal layer. The filling metal is over the top WF metal layer. The epitaxy structures are over the P-type region of the substrate and on opposite sides of the gate stack.

Abstract: A semiconductor device includes a substrate, a gate stack, and an epitaxy structure. The gate stack over the substrate and includes a gate dielectric layer, a bottom work function (WF) metal layer, a top WF metal layer, and a filling metal. The bottom WF metal layer is over the gate dielectric layer. The top WF metal layer is over and in contact with the bottom WF metal layer. At least one of the top and bottom WF metal layers includes dopants, and the top WF metal layer is thicker than the bottom WF metal layer. The filling metal is over the top WF metal layer. The epitaxy structure is over the substrate and adjacent the gate stack.

Abstract: The present disclosure generally relates to a gate-all-around (GAA) transistor. The GAA transistor may include regrown source/drain layers in source/drain stressors. Atomic ratio differences among the regrown source/drain layers are tuned to reduce strain mismatch among the semiconductor nanosheets. Alternatively, the GAA transistor may include strained channels formed using a layer stack of alternating semiconductor layers having different lattice constants.

Abstract: A method includes forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers over a substrate; forming a dummy gate structure across the fin structure; etching portions of the fin structure to expose portions of the substrate; forming source/drain stressors over the exposed portions of the substrate; after forming the source/drain stressors, removing the dummy gate structure; after removing the dummy gate structure, removing the first semiconductor layers such that the second semiconductor layers are suspended between the source/drain stressors; and forming a gate structure to surround each of the suspended second semiconductor layers. The source/drain stressors each comprise a first source/drain layer and a second source/drain layer over the first source/drain layer. An atomic concentration of a Group IV element or a Group V element in the second source/drain layer is greater than that in the first source/drain layer.

Abstract: A method of manufacturing a semiconductor device includes forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers on a substrate. The first and second semiconductor layers include first end portions on either side of a second portion along a length of the first and second semiconductor layers. The first and second semiconductor layers are formed of different materials. The second portion of the first semiconductor layers is removed to form spaces. A mask layer is formed over the second portion of an uppermost second semiconductor layer above the spaces. The first portions of first and second semiconductor layers are irradiated with radiation from a radiation source to cause material from the first portions of the first and second semiconductor layers to combine with each other.

Abstract: A semiconductor device includes a substrate, a gate stack, and an epitaxy structure. The gate stack over the substrate and includes a gate dielectric layer, a bottom work function (WF) metal layer, a top WF metal layer, and a filling metal. The bottom WF metal layer is over the gate dielectric layer. The top WF metal layer is over and in contact with the bottom WF metal layer. At least one of the top and bottom WF metal layers includes dopants, and the top WF metal layer is thicker than the bottom WF metal layer. The filling metal is over the top WF metal layer. The epitaxy structure is over the substrate and adjacent the gate stack.

Abstract: A method includes forming a first semiconductor layer over a substrate; forming a second semiconductor layer over the first semiconductor layer; forming a dummy gate structure over the second semiconductor layer; performing an etching process to form a recess in the first and second semiconductor layers; forming a epitaxy structure over in the recess, wherein the epitaxy structure is in contact with the first and second semiconductor layers; performing a solid phase diffusion process to form a doped region in the epitaxy structure, in which the doped region is in contact with the second semiconductor layer and is separated from the first semiconductor layer; and replacing the dummy gate structure with a metal gate structure.

Abstract: A method includes forming a fin structure over a substrate; forming a source/drain structure adjoining the fin structure, in which the source/drain structure includes tin; and exposing the source/drain structure to a boron-containing gas to diffuse boron into the source/drain structure to form a doped region in the source/drain structure.

Abstract: A semiconductor device includes a fin extending along a first direction over a substrate, and a gate structure extending in a second direction overlying the fin. The gate structure includes a gate dielectric layer overlying the fin, a gate electrode overlying the gate dielectric layer, and insulating gate sidewalls on opposing lateral surfaces of the gate electrode extending along the second direction. A source/drain region is formed in the fin in a region adjacent the gate electrode structure, and a stressor layer is between the source/drain region and the semiconductor substrate. The stressor layer includes GeSn or SiGeSn containing 1019 atoms cm?3 or less of a dopant, and a portion of the fin under the gate structure is a channel region.

Abstract: A method of manufacturing a semiconductor device includes forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers on a substrate. The first and second semiconductor layers include first end portions on either side of a second portion along a length of the first and second semiconductor layers. The first and second semiconductor layers are formed of different materials. The second portion of the first semiconductor layers is removed to form spaces. A mask layer is formed over the second portion of an uppermost second semiconductor layer above the spaces. The first portions of first and second semiconductor layers are irradiated with radiation from a radiation source to cause material from the first portions of the first and second semiconductor layers to combine with each other.

Abstract: A semiconductor device includes a fin extending along a first direction over a substrate, and a gate structure extending in a second direction overlying the fin. The gate structure includes a gate dielectric layer overlying the fin, a gate electrode overlying the gate dielectric layer, and insulating gate sidewalls on opposing lateral surfaces of the gate electrode extending along the second direction. A source/drain region is formed in the fin in a region adjacent the gate electrode structure, and a stressor layer is between the source/drain region and the semiconductor substrate. The stressor layer includes GeSn or SiGeSn containing 1019 atoms cm?3 or less of a dopant, and a portion of the fin under the gate structure is a channel region.

Abstract: A method of manufacturing a semiconductor device includes forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers on a substrate. The first and second semiconductor layers include first end portions on either side of a second portion along a length of the first and second semiconductor layers. The first and second semiconductor layers are formed of different materials. The second portion of the first semiconductor layers is removed to form spaces. A mask layer is formed over the second portion of an uppermost second semiconductor layer above the spaces. The first portions of first and second semiconductor layers are irradiated with radiation from a radiation source to cause material from the first portions of the first and second semiconductor layers to combine with each other.

Abstract: A method includes forming a fin structure over a substrate; forming a source/drain structure adjoining the fin structure, in which the source/drain structure includes tin; and exposing the source/drain structure to a boron-containing gas to diffuse boron into the source/drain structure to form a doped region in the source/drain structure.

Abstract: A method of manufacturing a semiconductor device includes forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers on a substrate. The first and second semiconductor layers include first end portions on either side of a second portion along a length of the first and second semiconductor layers. The first and second semiconductor layers are formed of different materials. The second portion of the first semiconductor layers is removed to form spaces. A mask layer is formed over the second portion of an uppermost second semiconductor layer above the spaces. The first portions of first and second semiconductor layers are irradiated with radiation from a radiation source to cause material from the first portions of the first and second semiconductor layers to combine with each other.

Abstract: A semiconductor device includes a fin extending along a first direction over a substrate, and a gate structure extending in a second direction overlying the fin. The gate structure includes a gate dielectric layer overlying the fin, a gate electrode overlying the gate dielectric layer, and insulating gate sidewalls on opposing lateral surfaces of the gate electrode extending along the second direction. A source/drain region is formed in the fin in a region adjacent the gate electrode structure, and a stressor layer is between the source/drain region and the semiconductor substrate. The stressor layer includes GeSn or SiGeSn containing 1019 atoms cm? or less of a dopant, and a portion of the fin under the gate structure is a channel region.