The present disclosure relates to semiconductor structures and, more particularly, to field effect transistors and methods of manufacture. The structure includes: at least one gate structure having source/drain regions; at least one isolation structure within the source/drain regions in a substrate material; and semiconductor material on a surface of the at least one isolation structure in the source/drain regions.

A semiconductor structure and a method for fabricating the same. The semiconductor structure includes at least a first channel region and a second channel region. The first channel region and the second channel region each include metal gate structures surrounding a different nanosheet channel layer. The metal gate structures of the first and second channel regions are respectively separated from each other by an unfilled gap. The method includes forming a gap fill layer between and in contact with gate structures surrounding nanosheet channel layers in multiple channel regions. Then, after the gap fill layer has been formed for each nanosheet stack, a masking layer is formed over the gate structures and the gap fill layer in at least a first channel region. The gate structures and the gap fill layer in at least a second channel region remain exposed.

A semiconductor device includes a substrate having a recess therein that is partially filled with at least two semiconductor active regions. The recess has sidewalls and a bottom that are sufficiently lined with corresponding substrate insulating layers that the at least two semiconductor active regions are electrically isolated from the substrate, which surrounds the sidewalls and bottom of the recess. A sidewall insulating layer is provided, which extends as a partition between first and second ones of the at least two semiconductor active regions, such that the first and second ones of the at least two semiconductor active regions are electrically isolated from each other. First and second gate electrodes are provided in the first and second active regions, respectively.

In some embodiments, the present disclosure relates to an integrated chip that includes a semiconductor device, a polysilicon isolation structure, and a first and second insulator liner. The semiconductor device is disposed on a frontside of a substrate. The polysilicon isolation structure continuously surrounds the semiconductor device and extends from the frontside of the substrate towards a backside of the substrate. The first insulator liner and second insulator liner respectively surround a first outermost sidewall and a second outermost sidewall of the polysilicon isolation structure. The substrate includes a monocrystalline facet arranged between the first and second insulator liners. A top of the monocrystalline facet is above bottommost surfaces of the polysilicon isolation structure, the first insulator liner, and the second insulator liner.

A semiconductor device includes an extremely thin semiconductor-on-insulator substrate (ETSOI) having a base substrate, a thin semiconductor layer and a buried dielectric therebetween. A device channel is formed in the thin semiconductor layer. Source and drain regions are formed at opposing positions relative to the device channel. The source and drain regions include an n-type material deposited on the buried dielectric within a thickness of the thin semiconductor layer. A gate structure is formed over the device channel.

A semiconductor device according to one embodiment of the present disclosure includes: a first low-permittivity region provided in a region that is between first metals in an in-plane direction of a semiconductor layer and below a lower surface of the first metal in a stacking direction of the semiconductor layer; and a second low-permittivity region provided in a region that is between a contact plug and the gate electrode in the in-plane direction and below the first low-permittivity region in the stacking direction. A planar region of the second low-permittivity region is at least partially different from that of the first low-permittivity region.

Provided is a semiconductor device. The semiconductor device includes a semiconductor substrate including monocrystalline silicon or polycrystalline silicon, a first insulating layer on the semiconductor substrate, the first insulating layer including a local region in which a portion of an upper surface of the first insulating layer is recessed, a channel layer provided in the local region of the first insulating layer, a silicide provided on one side surface of the channel layer, a control gate provided on the channel layer, a gate insulating film provided between the channel layer and the control gate, and a polarity control gate arranged so as to overlap an interface between the channel layer and the silicide, wherein the polarity control gate is spaced apart from the control gate, and the channel layer includes monocrystalline silicon.

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.

A method of forming a vertical fin field effect device is provided. The method includes, forming a vertical fin on a substrate, forming a masking block on the vertical fin, wherein the masking block extends a distance outward from the vertical fin sidewalls and endwalls, and a portion of the substrate surrounding the masking block is exposed. The method further includes removing at least a portion of the exposed portion of the substrate to form a recess and a fin mesa below the vertical fin, removing a portion of the fin mesa to form an undercut recess below an overhanging portion of the masking block, forming a spacer layer on the masking block and in the undercut recess, and removing a portion of the spacer layer to form an undercut spacer in the undercut recess.

An silicon-on-insulator substrate is provided in the present invention, including a handler, a polysilicon trap-rich layer formed on the handler, an oxide layer formed on the polysilicon trap-rich layer and a monocrystalline silicon layer formed directly on the oxide layer, wherein a bonding interface is between the monocrystalline silicon layer and the oxide layer.