An integrated circuit device includes a substrate including a first region and a second region, a first transistor in the first region, the first transistor being an N-type transistor and including a first silicon-germanium layer on the substrate, and a first gate electrode on the first silicon-germanium layer, and a second transistor in the second region and including a second gate electrode, the second transistor not having a silicon-germanium layer between the substrate and the second gate electrode.

A method includes providing a substrate having an n-type fin-like field-effect transistor (NFET) region and forming a fin structure in the NFET region. The fin structure includes a first layer having a first semiconductor material, and a second layer under the first layer and having a second semiconductor material different from the first semiconductor material. The method further includes forming a patterned hard mask to fully expose the fin structure in gate regions of the NFET region and partially expose the fin structure in at least one source/drain (S/D) region of the NFET region. The method further includes oxidizing the fin structure not covered by the patterned hard mask, wherein the second layer is oxidized at a faster rate than the first layer. The method further includes forming an S/D feature over the at least one S/D region of the NFET region.

A semiconductor device includes a substrate including a plurality of transistor devices formed thereon, at least an epitaxial structure formed in between the transistor devices, and a tri-layered structure formed on the epitaxial structure. The epitaxial structure includes a first semiconductor material and a second semiconductor material, and a lattice constant of the second semiconductor material is larger than a lattice constant of the first semiconductor material. The tri-layered structure includes an undoped epitaxial layer, a metal-semiconductor compound layer, and a doped epitaxial layer sandwiched in between the undoped epitaxial layer and the metal-semiconductor compound layer. The undoped epitaxial layer and the doped epitaxial layer include at least the second semiconductor material.

A method for forming semiconductor devices includes forming a highly doped region. A stack of alternating layers is formed on the substrate. The stack is patterned to form nanosheet structures. A dummy gate structure is formed over and between the nanosheet structures. An interlevel dielectric layer is formed. The dummy gate structures are removed. SG regions are blocked, and top sheets are removed from the nanosheet structures along the dummy gate trench. A bottommost sheet is released and forms a channel for a field effect transistor device by etching away the highly doped region under the nanosheet structure and layers in contact with the bottommost sheet. A gate structure is formed in and over the dummy gate trench wherein the bottommost sheet forms a device channel for the EG device.

A method of fabricating a semiconductor device is provided as follows. A channel layer is formed on a strain relaxed buffer (SRB) layer. A first etching process is performed on the channel layer and the SRB layer to form a plurality of trenches. The trenches penetrate through the channel layer and into the SRB layer to a first depth. First liners are formed on first sidewalls of the trenches having the first depth. The first liners cover the first sidewalls. A second etching process is performed on the SRB layer exposed through the trenches. The second etching process is performed on the SRB layer using a gas etchant having etch selectivity with respect to the first liners so that after the performing of the second etching process, the first liners remain on the first sidewalls.

A semiconductor structure includes a silicon carbide layer, which has a unit region and a termination region surrounding the unit region. A first guard ring structure is located in the termination region of the silicon carbide layer, and adjoins a top surface of the silicon carbide layer. The first guard ring structure may include at least one first guard ring well region. A second guard ring structure is located in the silicon carbide layer and below the first guard ring structure. The second guard ring structure may include at least one second guard ring well region, which corresponds to the at least one first guard ring well region in a vertical direction. A method for manufacturing the semiconductor structure is also provided.

An SiC semiconductor device includes an SiC semiconductor layer including an SiC monocrystal that is constituted of a hexagonal crystal and having a first main surface as a device surface facing a c-plane of the SiC monocrystal and has an off angle inclined with respect to the c-plane, a second main surface at a side opposite to the first main surface, and a side surface facing an a-plane of the SiC monocrystal and has an angle less than the off angle with respect to a normal to the first main surface when the normal is 0.

A semiconductor structure, including: a base substrate; an insulating layer on the base substrate, the insulating layer having a thickness between about 5 nm and about 100 nm; and an active layer comprising at least two pluralities of different volumes of semiconductor material comprising silicon, germanium, and/or silicon germanium, the active layer disposed over the insulating layer, the at least two pluralities of different volumes of semiconductor material comprising: a first plurality of volumes of semiconductor material having a tensile strain of at least about 0.6%; and a second plurality of volumes of semiconductor material having a compressive strain of at least about 0.6%. Also described is a method of preparing a semiconductor structure and a segmented strained silicon-on-insulator device.

A semiconductor structure, including: a base substrate; an insulating layer on the base substrate, the insulating layer having a thickness between about 5 nm and about 100 nm; and an active layer comprising at least two pluralities of different volumes of semiconductor material comprising silicon, germanium, and/or silicon germanium, the active layer disposed over the insulating layer, the at least two pluralities of different volumes of semiconductor material comprising: a first plurality of volumes of semiconductor material having a tensile strain of at least about 0.6%; and a second plurality of volumes of semiconductor material having a compressive strain of at least about 0.6%. Also described is a method of preparing a semiconductor structure and a segmented strained silicon-on-insulator device.

A semiconductor device includes a first silicon carbide region of a first conductivity type, a second silicon carbide region of a second conductivity type on the first region, and a third silicon carbide region of a second conductivity type on the second region. Fourth and fifth silicon carbide region of the first conductivity type are on the third region. A first electrode has a first portion between the fourth region and fifth region in a first direction. A metal silicide layer is between the first portion and the third region, between the first portion and the fourth region in the first direction, and between the first portion and the fifth silicon carbide region in the first direction.