A device includes a first fin and a second fin extending from a substrate, the first fin including a first recess and the second fin including a second recess, an isolation region surrounding the first fin and surrounding the second fin, a gate stack over the first fin and the second fin, and a source/drain region in the first recess and in the second recess, the source/drain region adjacent the gate stack, wherein the source/drain region includes a bottom surface extending from the first fin to the second fin, wherein a first portion of the bottom surface that is below a first height above the isolation region has a first slope, and wherein a second portion of the bottom surface that is above the first height has a second slope that is greater than the first slope.

A composite substrate is provided in some embodiments of the present disclosure, which includes a substrate, an insulation layer, a first silicon-containing layer and a first epitaxial layer. The insulation layer is disposed on the substrate. The first silicon-containing layer is disposed on the insulation layer, in which the first silicon-containing layer includes a plurality of group V atoms. The first epitaxial layer is disposed on the first silicon-containing layer, in which the first epitaxial layer includes a plurality of group III atoms. A distribution concentration of the group V atoms in the first silicon-containing layer increases as getting closer to the first epitaxial layer, and a distribution concentration of the group III atoms in the first epitaxial layer increases as getting closer to the first silicon-containing layer. A method of manufacturing a composite substrate is also provided in some embodiments of the present disclosure.

Materials containing picocrystalline quantum dots that form artificial atoms are disclosed. The picocrystalline quantum dots (in the form of born icosahedra with a nearly-symmetrical nuclear configuration) can replace corner silicon atoms in a structure that demonstrates both short range and long-range order as determined by x-ray diffraction of actual samples. A novel class of boron-rich compositions that self-assemble from boron, silicon, hydrogen and, optionally, oxygen is also disclosed. The preferred stoichiometric range for the compositions is (B.sub.12H.sub.w).sub.xSi.sub.yO.sub.z with 3≤w≤5, 2≤x≤4, 2≤y≤5 and 0≤z≤3. By varying oxygen content and the presence or absence of a significant impurity such as gold, unique electrical devices can be constructed that improve upon and are compatible with current semiconductor technology.

A method includes etching a semiconductor substrate to form a trench, with the semiconductor substrate having a sidewall facing the trench, and depositing a first semiconductor layer extending into the trench. The first semiconductor layer includes a first bottom portion at a bottom of the trench, and a first sidewall portion on the sidewall of the semiconductor substrate. The first sidewall portion is removed to reveal the sidewall of the semiconductor substrate. The method further includes depositing a second semiconductor layer extending into the trench, with the second semiconductor layer having a second bottom portion over the first bottom portion, and a second sidewall portion contacting the sidewall of the semiconductor substrate. The second sidewall portion is removed to reveal the sidewall of the semiconductor substrate.

A method for manufacturing a semiconductor device includes supplying a silicon-containing gas to a substrate having a recess formed in a surface of the substrate to deposit a silicon film in the recess, supplying, to the substrate, a first etching gas having a first etching profile in which an amount of etching for an upper portion of the recess in a depth direction and an amount of etching for a lower portion of the recess in the depth direction are different from each other, to etch the silicon film in the recess, supplying, to the substrate, a second etching gas having a second etching profile that is different from the first etching profile of the first etching gas to etch the silicon film in the recess, and additionally depositing the silicon film on the already deposited silicon film etched by the second etching gas.

A method for forming a semiconductor device structure is provided. The method includes forming an n-type doped region in a semiconductor substrate and forming a semiconductor stack over the semiconductor substrate. The semiconductor stack has multiple sacrificial layers and multiple semiconductor layers laid out alternately. The method also includes introducing n-type dopants from the n-type doped region into the semiconductor stack during the forming of the semiconductor stack. The method further includes patterning the semiconductor stack to form a fin structure and forming a dummy gate stack to wrap around a portion of the fin structure. In addition, the method includes removing the dummy gate stack and the sacrificial layers to release multiple semiconductor nanostructures made up of remaining portions of the semiconductor layers. The method includes forming a metal gate stack to wrap around the semiconductor nanostructures.

A method for making a semiconductor device may include forming a semiconductor layer, and forming a superlattice adjacent the semiconductor layer and including stacked groups of layers. Each group of layers may include stacked base semiconductor monolayers defining a base semiconductor portion, and at least one oxygen monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The at least one oxygen monolayer of a given group of layers may comprise an atomic percentage of .sup.18O greater than 10 percent.

A tilted nanowire structure is provided which has an increased gate length as compared with a horizontally oriented semiconductor nanowire at the same pitch. Such a structure avoids complexity required for vertical transistors and can be fabricated on a bulk semiconductor substrate without significantly changing/modifying standard transistor fabrication processing.

A semiconductor gate-all-around (GAA) device may include a semiconductor substrate, source and drain regions on the semiconductor substrate, a plurality of semiconductor nanostructures extending between the source and drain regions, a gate surrounding the plurality of semiconductor nanostructures in a gate-all-around arrangement, and a dopant diffusion liner adjacent at least one of the source and drain regions and comprising a first superlattice. The first superlattice may include a plurality of stacked groups of layers, with each group of layers comprising a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions.

A method of forming a structure having a coating layer includes the following steps: providing a substrate; coating a fluid on the surface of the substrate, where the fluid includes a carrier and a plurality of silicon-containing nanoparticles; and performing a heating process to remove the carrier and convert the silicon-containing nanoparticles into a silicon-containing layer, a silicide layer, or a stack layer including the silicide layer and the silicon-containing layer.