Material systems for source region, drain region, and a semiconductor body of transistor devices in which the semiconductor body is electrically insulated from an underlying substrate are selected to reduce or eliminate a band to band tunneling (BTBT) effect between different energetic bands of the semiconductor body and one or both of the source region and the drain region. This can be accomplished by selecting a material for the semiconductor body with a band gap that is larger than a band gap for material(s) selected for the source region and/or drain region.

A method for fabricating a semiconductor device includes providing a fin in a first region of a substrate. The fin includes a plurality of a first type of epitaxial layers and a plurality of a second type of epitaxial layers. A portion of a layer of the second type of epitaxial layers in a channel region of the first fin is removed to form a first gap between a first layer of the first type of epitaxial layers and a second layer of the first type of epitaxial layers. A first portion of a first gate structure is formed within the first gap and extending from a first surface of the first layer of the first type of epitaxial layers to a second surface of the second layer of the first type of epitaxial layers. A first source/drain feature is formed abutting the first portion of the first gate structure.

A method includes forming a fin extending from a substrate; depositing a liner over a top surface and sidewalls of the fin, where the minimum thickness of the liner is dependent on selected according to a first germanium concentration of the fin; forming a shallow trench isolation (STI) region adjacent the fin; removing a first portion of the liner on sidewalls of the fin, the first portion of the liner being above a topmost surface of the STI region; and forming a gate stack on sidewalls and a top surface of the fin, where the gate stack is in physical contact with the liner.

A semiconductor device is provided. The semiconductor device includes a plurality of first semiconductor nanostructures formed over a substrate, and a first S/D structure formed on sidewall surfaces of the first semiconductor nanostructures. The semiconductor device includes a plurality of second semiconductor nanostructures formed over the substrate, and a second S/D structure formed on sidewall surfaces of the second semiconductor nanostructures. The semiconductor device includes an isolation structure formed between the first S/D structure and the second S/D structure, and the isolation structure has a first sidewall surface in direct contact with the first S/D structure and a second sidewall surface in direct contact with the second S/D structure.

A method of fabricating a semiconductor device includes providing a first fin extending from a substrate. In some embodiments, the method further includes forming a first gate stack over the first fin. In various examples, the method further includes forming a first doped layer along a surface of the first fin including beneath the first gate stack. In some cases, a first dopant species of the first doped layer is of a same polarity as a second dopant species of a source/drain feature of the semiconductor device.

Methods of forming a metal gate structure of a stacked multi-gate device are provided. A method according to the present disclosure includes depositing a titanium nitride (TiN) layer over a channel region that includes bottom channel layers and top channel layers, depositing a dummy fill layer to cover sidewalls of the bottom channel layers, after the depositing of the dummy fill layer, selectively forming a blocking layer over the TiN layer along sidewalls of the top channel layers, selectively removing the dummy fill layer to release the bottom channel layers, selectively depositing a first work function metal layer to wrap around each of the bottom channel layers, forming a gate isolation layer over a top surface of the first work function metal layer, removing the blocking layer, releasing the top channel layers, and selectively depositing a second work function metal layer to wrap around each of the top channel layers.

A semiconductor device includes a fin-shaped structure on a substrate, a single diffusion break (SDB) structure in the fin-shaped structure to divide the first fin-shaped structure into a first portion and a second portion, and more than two gate structures on the SDB structure. Preferably, the more than two gate structures include a first gate structure, a second gate structure, a third gate structure, and a fourth gate structure disposed on the SDB structure.

Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a plurality of nanostructures over a substrate, and a gate electrode surrounding the nanostructures. The semiconductor device structure includes a source/drain portion adjacent to the gate electrode, and a semiconductor layer between the gate electrode and the source/drain portion.

A semiconductor device includes: a cell region including active regions where components of transistors are formed; the cell region are arranged to function as a D flip-flop that includes a primary latch (having a first sleepy inverter and a first non-sleepy (NS) inverter), a secondary latch (having a second sleepy inverter and a second NS inverter), and a clock buffer (having third and fourth NS inverters). The transistors are grouped: a first group has a standard threshold voltage (Vt_std); a second group has a low threshold voltage (Vt_low); and an optional third group has a high threshold voltage (Vt_high). The transistors which comprise the first or second NS inverter have Vt_low. Alternatively, the transistors of the cell region are further arranged to function as a scan-insertion type of D flip-flop (SDFQ) that further includes a multiplexer; and the transistors of the multiplexer have Vt_low.

A semiconductor device includes a first transistor in a first region of a substrate and a second transistor in a second region of the substrate. The first transistor includes multiple first semiconductor patterns; a first gate electrode; a first gate dielectric layer; a first source/drain region; and an inner-insulating spacer. The second transistor includes multiple second semiconductor patterns; a second gate electrode; a second gate dielectric layer; and a second source/drain region. The second gate dielectric layer extends between the second gate electrode and the second source/drain region and is in contact with the second source/drain region. The first source/drain region is not in contact with the first gate dielectric layer.