Abstract: Semiconductor devices include a stack of vertically arranged channel layers. A gate stack is formed above, between, and around the vertically arranged channel layers. Source and drain regions and source and drain conductive contacts are formed. Inner spacers are formed between the vertically arranged channel layers, each having an inner air gap and a recessed layer formed from a first dielectric material. Outer spacers are formed between the gate stack and the source and drain conductive contacts, each having a second dielectric material that is pinched off to form an outer air gap.

Abstract: Channel engineering is employed to obtain a gate-all-around field-effect transistor having an asymmetric threshold voltage. A dual channel profile enables a steep potential distribution near the source side that enhances the lateral channel electric field and thus increases the carrier mobility.

Abstract: A method of forming a source/drain contact is provided. The method includes forming a sacrificial layer on a source/drain, and depositing an oxidation layer on the sacrificial layer. The method further includes heat treating the oxidation layer and the sacrificial layer to form a modified sacrificial layer. The method further includes forming a protective liner on the modified sacrificial layer, and depositing an interlayer dielectric layer on the protective liner. The method further includes forming a trench in the interlayer dielectric layer that exposes a portion of the protective liner.

Abstract: A method for making first and second superimposed transistors, including: making, on a substrate, a stack of several semiconducting nanowires; etching a first nanowire so that a remaining portion of the first nanowire forms a channel of the first transistor; etching a second nanowire arranged between the substrate and the first nanowire, so that a remaining portion of the second nanowire forms a channel of the second transistor and has a greater length than that of the remaining portion of the first nanowire; making second source and drain regions in contact with ends of the remaining portion of the second nanowire; depositing a first dielectric encapsulation layer covering the second source and drain regions and forming vertical insulating portions; making first source and drain regions in contact with ends of the remaining portion of the first nanowire and insulated from the second source and drain regions by the vertical insulating portions.

Abstract: A method of forming a source/drain contact is provided. The method includes forming a sacrificial layer on a source/drain, and depositing an oxidation layer on the sacrificial layer. The method further includes heat treating the oxidation layer and the sacrificial layer to form a modified sacrificial layer. The method further includes forming a protective liner on the modified sacrificial layer, and depositing an interlayer dielectric layer on the protective liner. The method further includes forming a trench in the interlayer dielectric layer that exposes a portion of the protective liner.

Abstract: Vertical transport field effect transistors (FETs) having improved device performance are provided. Notably, vertical transport FETs having a gradient threshold voltage are provided. The gradient threshold voltage is provided by introducing a threshold voltage modifying dopant into a physically exposed portion of a metal gate layer composed of an n-type workfunction TiN. The threshold voltage modifying dopant changes the threshold voltage of the original metal gate layer.

Abstract: A FinFET having an asymmetric threshold voltage distribution is provided by forming a halo ion implantation region in a semiconductor fin, and in close proximity to a source region, of the FinFET. The halo ion implantation region is self-aligned to an outermost sidewall surface of the functional gate structure of the FinFET and it has a higher dopant concentration than the remaining portion of the channel region.

Abstract: A semiconductor structure is provided in which an nFET nanosheet stack of suspended silicon channel material nanosheets is present in an nFET device region and a pFET nanosheet stack of suspended silicon germanium alloy channel material nanosheets is present in a pFET device region. The silicon channel material nanosheets of the nFET nanosheet stack are off-set by one nanosheet from the silicon germanium alloy channel material nanosheets of the pFET nanosheet stack.

Abstract: Embodiments of the invention are directed to a configuration of nanosheet FET devices in a first region of a substrate. Each of the nanosheet FET devices in the first region includes a first channel nanosheet, a second channel nanosheet over the first channel nanosheet, a first gate structure around the first channel nanosheet, and a second gate structure around the second channel nanosheet, wherein the first gate structure and the second gate structure pinch off in a pinch off area between the first gate structure and the second gate structure. The first gate structure includes a doped region, and the second gate structure includes a doped region. At least a portion of the pinch off area is undoped.

Abstract: A method of fabricating a semiconductor device includes providing a high-k dielectric layer arranged on a channel region including a first transistor area and a second transistor area. The method further includes depositing a multivalent oxide layer directly on the high-k dielectric layer of the first transistor area. The method includes depositing a first work function metal on the multivalent oxide layer of the first transistor area and directly on the high-k dielectric layer of the second transistor area.

Abstract: A method of forming a source/drain contact is provided. The method includes forming a sacrificial layer on a source/drain, and depositing an oxidation layer on the sacrificial layer. The method further includes heat treating the oxidation layer and the sacrificial layer to form a modified sacrificial layer. The method further includes forming a protective liner on the modified sacrificial layer, and depositing an interlayer dielectric layer on the protective liner. The method further includes forming a trench in the interlayer dielectric layer that exposes a portion of the protective liner.

Abstract: A method is presented for reducing external resistance of a vertical field-effect-transistor (FET). The method includes forming a plurality of fins over a sacrificial layer disposed over a substrate, selectively removing the sacrificial layer to form an etch stop layer in direct contact with the substrate, disposing embedded bottom source/drain regions between a bottom portion of the plurality of fins and the etch stop layer, disposing encapsulation layers over the plurality of fins, recessing at least one of the encapsulation layers to expose top portions of the plurality of fins, forming top spacers adjacent the top portions of the plurality of fins, and forming top source/drain regions over the top portions of the plurality of fins.

Abstract: A method of fabricating a semiconductor device includes providing a high-k dielectric layer arranged on a channel region including a first transistor area and a second transistor area. The method further includes depositing a multivalent oxide layer directly on the high-k dielectric layer of the first transistor area. The method includes depositing a first work function metal on the multivalent oxide layer of the first transistor area and directly on the high-k dielectric layer of the second transistor area.

Abstract: An I/O device nanosheet material stack of suspended semiconductor channel material nanosheet is provided above a semiconductor substrate. A physically exposed portion of each suspended semiconductor channel material nanosheet is thinned to increase the inter-nanosheet spacing between each vertically stacked semiconductor channel material nanosheet. An I/O device functional gate structure is formed wrapping around the thinned portion of each suspended semiconductor channel material nanosheet.

Abstract: Vertical transport field effect transistors (FETs) having improved device performance are provided. Notably, vertical transport FETs having a gradient threshold voltage are provided. The gradient threshold voltage is provided by forming a gradient threshold voltage adjusting gate dielectric structure between the bottom drain region of the FET and the top source region of the FET. The gradient threshold voltage adjusting gate dielectric structure includes a doped interface high-k gate dielectric material that is located in proximity to the bottom drain region and a non-doped high-k dielectric material that is located in proximity to the top source region. The non-doped high-k dielectric material has a higher threshold voltage than the doped interface high-k gate dielectric.

Abstract: Vertical transport field effect transistors (FETs) having improved device performance are provided. Notably, vertical transport FETs having a gradient threshold voltage are provided. The gradient threshold voltage is provided by forming a gradient threshold voltage adjusting gate dielectric structure between the bottom drain region of the FET and the top source region of the FET. The gradient threshold voltage adjusting gate dielectric structure includes a doped interface high-k gate dielectric material that is located in proximity to the bottom drain region and a non-doped high-k dielectric material that is located in proximity to the top source region. The non-doped high-k dielectric material has a higher threshold voltage than the doped interface high-k gate dielectric.

Abstract: Vertical transport field effect transistors (FETs) having improved device performance are provided. Notably, vertical transport FETs having a gradient threshold voltage are provided. The gradient threshold voltage is provided by introducing a threshold voltage modifying dopant into a physically exposed portion of a metal gate layer composed of an n-type workfunction TiN. The threshold voltage modifying dopant changes the threshold voltage of the original metal gate layer.

Abstract: A semiconductor device includes a first gate-all-around field-effect transistor (GAA FET) device including a first gate stack having first channels, interfacial layers formed around the first channels, and dielectric material including first and second portions having respective thicknesses formed on the first interfacial layers. The semiconductor device further includes a second GAA FET device including a second gate stack having second channels, the interfacial layers formed around the second channels, and the dielectric material formed on the second interfacial layers. A threshold voltage (Vt) shift associated with the semiconductor device is achieved based on a thickness of the first portion of the dielectric material.

Abstract: A sacrificial inner dielectric spacer is formed on physically exposed sidewalls of each recessed semiconductor channel material nanosheet of a nanosheet material stack that further includes recessed sacrificial semiconductor material nanosheets that have an inner dielectric spacer formed on physically exposed sidewalls thereof. A local isolation region is then formed by selective epitaxial growth on a surface of a semiconductor substrate containing the nanosheet material stack. After forming the local isolation region, the sacrificial inner dielectric spacers are removed and a source/drain region is formed on the physically exposed surface of each recessed semiconductor channel material nanosheet. A portion of the source/drain structure is formed in a gap located between each neighboring pair of vertically spaced apart inner dielectric spacers.

Abstract: VTFET devices having a differential top spacer are provided. In one aspect, a method of forming a VTFET device includes: patterning fins in a wafer including NFET and PFET fins; forming bottom source and drains at a base of the NFET/PFET fins; forming bottom spacers on the bottom source and drains; forming gate stacks alongside the NFET/PFET fins that include a same workfunction metal on top of a gate dielectric; annealing the gate stacks which generates oxygen vacancies in the gate dielectric; forming top spacers that include an oxide spacer layer in contact with only the gate stacks alongside the PFET fins, wherein the oxide spacer layer supplies oxygen filling the oxygen vacancies in the gate dielectric only in the gate stacks alongside the PFET fins; and forming top source and drains above the gate stacks at the tops of the NFET/PFET fins. A VTFET device is also provided.