A method for forming a semiconductor device structure is provided. The method includes providing a substrate having a base, a first fin, and a second fin over the base. The method includes forming a gate stack over the first fin and the second fin. The method includes forming a first spacer over gate sidewalls of the gate stack and a second spacer adjacent to the second fin. The method includes partially removing the first fin and the second fin. The method includes forming a first source/drain structure and a second source/drain structure in the first trench and the second trench respectively. A first ratio of a first height of the first merged portion to a second height of a first top surface of the first source/drain structure is greater than or equal to about 0.5.

In an embodiment, a method includes: patterning a lower semiconductor nanostructure, an upper semiconductor nanostructure, and a dummy nanostructure, the dummy nanostructure disposed between the lower semiconductor nanostructure and the upper semiconductor nanostructure, the dummy nanostructure including doped silicon; forming an opening between the lower semiconductor nanostructure and the upper semiconductor nanostructure by etching the doped silicon of the dummy nanostructure; forming an isolation structure in the opening; and depositing a gate dielectric around the isolation structure, the upper semiconductor nanostructure, and the lower semiconductor nanostructure.

A method for forming a semiconductor device structure is provided. The method includes forming a first fin structure and a second fin structure. Each of the first fin structure and the second fin structure has multiple sacrificial layers and multiple semiconductor layers laid out in an alternating manner, and the first fin structure is substantially as wide as the second fin structure. The method also includes forming a gate stack wrapped around the first fin structure and the second fin structure. The method further includes simultaneously removing the sacrificial layers of the first fin structure and the second fin structure. Remaining portions of the semiconductor layers of the first fin structure form multiple first semiconductor nanostructures, and remaining portions of the semiconductor layers of the second fin structure form multiple second semiconductor nanostructures. Each of the first semiconductor nanostructures is thicker than each of the second semiconductor nanostructures.

Method to implement heat dissipation multilayer and reduce thermal boundary resistance for high power consumption semiconductor devices is provided. The heat dissipation multilayer comprises a first crystalline layer that possesses a first phonon frequency range, a second crystalline layer that has a second phonon frequency range which does not overlap with the first phonon frequency range, and an amorphous layer located between the first and second crystalline layers. The amorphous layer has a third phonon frequency range that overlaps both the first and second phonon frequency ranges.

A semiconductor device may include one or more transistor structures that include a plurality of source/drain regions and a gate structure between the source/drain regions. The semiconductor device may further include one or more dielectric layers between a source/drain contact structure and a gate structure of the one or more of the transistor structures. The one or more dielectric layers may be manufactured using on oxidation treatment process to tune the dielectric constant of the one or more dielectric layers. The dielectric constant of the one or more dielectric layers may be tuned to reduce the parasitic capacitance between the source/drain contact structure and the gate structure (which are conductive structures). In particular, the dielectric constant of the one or more spacer dielectric may be tuned using the oxidation treatment process to lower the as-deposited dielectric constant of the one or more dielectric layers.

A semiconductor device with a barrier layer between a gate structure and gate spacer layers, and a method of fabricating the same are disclosed. The a method includes forming a fin structure on a substrate, forming a polysilicon structure on the fin structure, performing a nitridation operation to form a barrier layer on the polysilicon structure and the fin structure, forming gate spacer layers on the barrier layer, forming a source/drain region in the fin structure and adjacent to the barrier layer, annealing the gate spacer layers, and replacing the polysilicon structure with a gate structure.

A method includes forming an epitaxial source/drain region in a substrate; forming a first inter-layer dielectric over the epitaxial source/drain region; forming a gate stack over the substrate and adjacent to the first inter-layer dielectric; forming a gate mask over the gate stack; forming a source/drain plug through the first inter-layer dielectric and electrically connected to the epitaxial source/drain region; depositing a dielectric layer over the gate mask and the first inter-layer dielectric, the dielectric layer having a different etch selectivity than the gate mask; forming a second inter-layer dielectric over the dielectric layer; etching an opening through the second inter-layer dielectric and the dielectric layer, the opening exposing the source/drain plug and the gate mask; and forming a conductive feature in the opening, the conductive feature being electrically connected to the source/drain plug.

Provided is a three-dimension (3D) stacked semiconductor device which includes: a 1.sup.stsource/drain region connected to a 1.sup.st channel structure; and a 2.sup.nd source/drain region, above the 1.sup.st source/drain region, connected to a 2.sup.nd channel structure above the 1.sup.st channel structure, wherein the 2.sup.nd channel structure has a smaller length than the 1.sup.st channel structure in a channel-length direction, in which the 2.sup.nd source/drain region is connected to a 3.sup.rd source/drain region through the 2.sup.nd channel structure.

A microelectronic device including an analog MOS transistor. The analog transistor has a body well having a first conductivity type in a semiconductor material of a substrate of the microelectronic device. The body well extends deeper in the substrate than a field relief dielectric layer at the top surface of the semiconductor material. The analog transistor has a drain well and a source well having a second, opposite, conductivity type in the semiconductor material, both contacting the body well. The drain well and the source well extend deeper in the substrate than the field relief dielectric layer. The analog transistor has a gate on a gate dielectric layer over the body well. The drain well and the source well extend partway under the gate at the top surface of the semiconductor material.

There is provided a semiconductor device capable of improving electrical characteristics and integration density. The semiconductor device includes an active pattern protruding from a substrate, the active pattern including long sidewalls extending in a first direction and opposite to each other in a second direction, a lower epitaxial pattern on the substrate and covering a part of the active pattern, a gate electrode on the lower epitaxial pattern and extending along the long sidewalls of the active pattern, and an upper epitaxial pattern on the active pattern and connected to an upper surface of the active pattern. The active pattern includes short sidewalls connecting with the long sidewalls of the active pattern, and at least one of the short sidewalls of the active pattern has a curved surface.