After formation of a disposable gate structure, a raised active semiconductor region includes a vertical stack, from bottom to top, of an electrical-dopant-doped semiconductor material portion and a carbon-doped semiconductor material portion. A planarization dielectric layer is deposited over the raised active semiconductor region, and the disposable gate structure is replaced with a replacement gate structure. A contact via cavity is formed through the planarization dielectric material layer by an anisotropic etch process that employs a fluorocarbon gas as an etchant. The carbon in the carbon-doped semiconductor material portion retards the anisotropic etch process, and the carbon-doped semiconductor material portion functions as a stopping layer for the anisotropic etch process, thereby making the depth of the contact via cavity less dependent on variations on the thickness of the planarization dielectric layer or pattern factors.

A method of forming a variable spacer in a vertical transistor device includes forming a first source/drain of a first transistor on a substrate; forming a second source/drain of a second transistor on the substrate adjacent to the first source/drain, an isolation region arranged in the substrate between the first source/drain and the second source/drain; depositing a spacer material on the first source/drain; depositing the spacer material on the second source/drain; forming a first channel extending from the first source drain and through the spacer material; forming a second channel extending from the second source/drain and through the spacer material; wherein the spacer material on the first source/drain forms a first spacer and the spacer material on the second source/drain forms a second spacer, the first spacer being different in thickness than the second spacer.

A method of forming a variable spacer in a vertical transistor device includes forming a first source/drain of a first transistor on a substrate; forming a second source/drain of a second transistor on the substrate adjacent to the first source/drain, an isolation region arranged in the substrate between the first source/drain and the second source/drain; depositing a spacer material on the first source/drain; depositing the spacer material on the second source/drain; forming a first channel extending from the first source drain and through the spacer material; forming a second channel extending from the second source/drain and through the spacer material; wherein the spacer material on the first source/drain forms a first spacer and the spacer material on the second source/drain forms a second spacer, the first spacer being different in thickness than the second spacer.

A method of forming a semiconductor structure may include: forming a first dielectric layer having a first thickness over a substrate; removing a first portion of the first dielectric layer to expose a second region of the substrate; forming a second dielectric layer having a second thickness over the second region of the substrate; removing a second portion of the first dielectric layer to expose a third region of the substrate; forming a third dielectric layer having a third thickness over the third region of the substrate; and forming a first plurality of gate stacks comprising the first dielectric layer in a first region of the substrate, a second plurality of gate stacks comprising the second dielectric layer in the second region of the substrate, and a third plurality of gate stacks comprising the third dielectric layer in the third region of the substrate.

A semiconductor device includes first and second fins on first and second regions of a substrate, a first trench overlapping a vertical end portion of the first fin and including first upper and lower portions, the first upper and lower portions separated by an upper surface of the first fin, a second trench overlapping a vertical end portion of the second fin and including second upper and lower portions separated by an upper surface of the second fin, a first dummy gate electrode including first metal oxide and filling layers, the first metal oxide layer filling the first lower portion of the first trench and is along a sidewall of the first upper portion of the first trench, and a second dummy gate electrode filling the second trench and including second metal oxide and filling layers, the second metal oxide layer extending along sidewalls of the second trench.

A semiconductor device includes channel layers disposed over a substrate, a source/drain region disposed over the substrate, a gate dielectric layer disposed on and wrapping each of the channel layers, and a gate electrode layer disposed on the gate dielectric layer and wrapping each of the channel layers. Each of the channel layers includes a semiconductor wire made of a first semiconductor material. The semiconductor wire extends into the source/drain region. The semiconductor wire in the source/drain regions is wrapped around by a second semiconductor material.

In a method for manufacturing a semiconductor device, a dummy gate layer and a hard mask layer are sequentially formed on a substrate. A first doped portion is formed in the dummy gate layer, and has an etching selectivity with respect to the other portion of the dummy gate layer. Etching masks are formed on portions of the hard mask layer. The hard mask layer and the dummy gate layer are etched to pattern the first doped portion and the other portion of the dummy gate layer into first dummy gates and second dummy gates. The first dummy gates and the second dummy gates have different widths. A dielectric layer is formed to peripherally enclose each of the first dummy gates and each of the second dummy gates. The first dummy gates and the second dummy gates are replaced with first metal gates and second metal gates.

An integrated circuit (IC) device includes a first nanostructure, a second nanostructure, a first gate structure, a first source/drain epitaxial structure, and a dielectric isolation layer. The first nanostructure is spaced apart from a semiconductor substrate by a first spacing. The second nanostructure is above and spaced apart from the first nanostructure by a second spacing less than the first spacing. The first gate structure surrounds the first nanostructure and the second nanostructure. The first source/drain epitaxial structure is adjacent to both the first nanostructure and the second nanostructure. The dielectric isolation layer is between the first source/drain epitaxial structure and the semiconductor substrate. A top surface of the dielectric isolation layer is higher than a top surface of the semiconductor substrate and lower than a bottom surface of the first nanostructure.

A method for fabricating a semiconductor device includes the steps of first providing a substrate having a first transistor region and a second transistor region and then forming a first gate structure on the first transistor region and a second gate structure on the second transistor region, in which the first gate structure includes a first hard mask, the second gate structure includes a second hard mask, and the first hard mask and the second hard mask have different thicknesses. Next, a patterned mask is formed around the first gate structure and the second gate structure, and then part of the first hard mask is removed.

An integrated circuit includes a first replacement gate structure. The first replacement gate structure includes a layer of a first barrier material that is less than 20 in thickness and a layer of a p-type workfunction material. The replacement gate structure is less than about 50 nm in width.