Abstract: A device comprise a first semiconductor channel layer over a substrate, a second semiconductor channel layer over the first semiconductor channel layer, and source/drain epitaxial structures on opposite sides of the first semiconductor channel layer and opposite sides of the second semiconductor channel layer. A compressive strain in the second semiconductor channel layer is greater than a compressive strain in the first semiconductor channel layer. The source/drain epitaxial structures each comprise a first region interfacing the first semiconductor channel layer and a second region interfacing the second semiconductor channel layer, and the first region has a composition different from a composition of the second region.

Abstract: A semiconductor device includes a first layer that includes a first semiconductor material disposed on a semiconductor substrate, and a second layer of a second semiconductor material disposed on the first layer. The semiconductor substrate includes Si. The first semiconductor material and the second semiconductor material are different. The second semiconductor material is formed of an alloy including a first element and Sn. A surface region of an end portion of the second layer at both ends of the second layer has a higher concentration of Sn than an internal region of the end portion of the second layer. The surface region surrounds the internal region.

Abstract: A semiconductor device includes a first layer that includes a first semiconductor material disposed on a semiconductor substrate, and a second layer of a second semiconductor material disposed on the first layer. The semiconductor substrate includes Si. The first semiconductor material and the second semiconductor material are different. The second semiconductor material is formed of an alloy including a first element and Sn. A surface region of an end portion of the second layer at both ends of the second layer has a higher concentration of Sn than an internal region of the end portion of the second layer. The surface region surrounds the internal region.

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: The present disclosure is directed to semiconductor structures with source/drain epitaxial stacks having a low-melting point top layer and a high-melting point bottom layer. For example, a semiconductor structure includes a gate structure disposed on a fin and a recess formed in a portion of the fin not covered by the gate structure. Further, the semiconductor structure includes a source/drain epitaxial stack disposed in the recess, where the source/drain epitaxial stack has bottom layer and a top layer with a higher activated dopant concentration than the bottom layer.

Abstract: A device includes plural semiconductor fins, a gate structure, an interlayer dielectric (ILD) layer, and an isolation dielectric. The gate structure is across the semiconductor fins. The ILD surrounds the gate structure. The isolation dielectric is at least between the semiconductor fins and has a thermal conductivity greater than a thermal conductivity of the ILD layer.

Abstract: The present disclosure is directed to semiconductor structures with source/drain epitaxial stacks having a low-melting point top layer and a high-melting point bottom layer. For example, a semiconductor structure includes a gate structure disposed on a fin and a recess formed in a portion of the fin not covered by the gate structure. Further, the semiconductor structure includes a source/drain epitaxial stack disposed in the recess, where the source/drain epitaxial stack has bottom layer and a top layer with a higher activated dopant concentration than the bottom layer.

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: 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 of manufacturing a semiconductor device includes forming an alloy semiconductor material layer comprising a first element and a second element on a semiconductor substrate. A mask is formed on the alloy semiconductor material layer to provide a masked portion and an unmasked portion of the alloy semiconductor material layer. The unmasked portion of the alloy semiconductor material layer not covered by the mask is irradiated with radiation from a radiation source to transform the alloy semiconductor material layer so that a surface region of the unmasked portion of the alloy semiconductor material layer has a higher concentration of the second element than an internal region of the unmasked portion of the alloy semiconductor material layer. The surface region surrounds the internal region.

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 semiconductor device includes a first layer of a first semiconductor material disposed on a semiconductor substrate and a second layer of a second semiconductor material disposed on the first layer. The second semiconductor material is formed of an alloy that includes a first element and a second element. The first semiconductor material and the second semiconductor material are different. A gate structure is disposed on a first portion of the second layer. A surface region of a second portion of the second layer not covered by the gate structure has a higher concentration of the second element than an internal region of the second portion of the second layer, and the surface region surrounds the internal region.

Abstract: A semiconductor device includes a substrate, a channel structure and a metal gate structure. The channel structure protrudes above the substrate. The channel structure includes alternately stacked first portions and second portions having widths greater than widths of the first portions, and the first portions and the second portions are made of the same semiconductor material. The metal gate structure wraps around the channel structure.

Abstract: The present disclosure is directed to semiconductor structures with source/drain epitaxial stacks having a low-melting point top layer and a high-melting point bottom layer. For example, a semiconductor structure includes a gate structure disposed on a fin and a recess formed in a portion of the fin not covered by the gate structure. Further, the semiconductor structure includes a source/drain epitaxial stack disposed in the recess, where the source/drain epitaxial stack has bottom layer and a top layer with a higher activated dopant concentration than the bottom 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 device includes plural semiconductor fins, a gate structure, an interlayer dielectric (ILD) layer, and an isolation dielectric. The gate structure is across the semiconductor fins. The ILD surrounds the gate structure. The isolation dielectric is at least between the semiconductor fins and has a thermal conductivity greater than a thermal conductivity of the ILD layer.

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 of forming a semiconductor device includes forming a doped region on a semiconductor substrate, in which the doped region comprises an impurity therein, and performing a laser anneal process to the doped region with a process gas containing a dopant gas, in which the dopant gas and the impurity comprise the same chemical element.

Abstract: A device includes a non-insulator structure, a first ILD layer, a first thermal via, and a first electrical via. The first ILD is over the non-insulator structure. The first thermal via is through the first ILD layer and in contact with the non-insulator structure. The first electrical via is through the first ILD layer and in contact with the non-insulator structure. The first thermal via and the first electrical via have different materials and the same height.