Techniques to form semiconductor devices that include forksheet transistors with a self-aligned dielectric spine. In an example, first and second semiconductor devices have first and second semiconductor regions, respectively, extending in a first direction between corresponding source or drain regions. The first and second semiconductor regions may include any number of nanosheets with first and second gate structures extending around three sides of each of the first and second semiconductor regions, respectively. A dielectric spine extends in the first direction directly between the first and second semiconductor regions. In an example, the gate dielectric of each of the first and second gate structures is still present between the first and second semiconductor regions and the dielectric spine. An uppermost width of the dielectric spine may be smaller (e.g., 5 nm or more smaller) than a lower width of the dielectric spine that is between the first and second gate structures.

Structures with features formed by self-aligned double patterning and methods of self-aligned multiple patterning. The structure comprises a first field-effect transistor including a first gate and a first protrusion projecting laterally from the first gate, and a second field-effect transistor including a second gate and a second protrusion projecting laterally from the second gate. The second gate and the second protrusion are spaced in a lateral direction from the first gate and the first protrusion. The structure further comprises a gate contact connecting the first protrusion of the first gate to the second protrusion the second gate.

Semiconductor structures and methods of fabrication are provided. A method according to the present disclosure includes receiving a workpiece that includes an active region over a substrate and having first semiconductor layers interleaved by second semiconductor layers, and a dummy gate stack over a channel region of the active region, etching source/drain regions of the active region to form source/drain trenches that expose sidewalls of the active region, selectively and partially etching second semiconductor layers to form inner spacer recesses, forming inner spacer features in the inner spacer recesses, forming channel extension features on exposed sidewalls of the first semiconductor layers, forming source/drain features over the source/drain trenches, removing the dummy gate stack, selectively removing the second semiconductor layers to form nanostructures in the channel region, forming a gate structure to wrap around each of the nanostructures. The channel extension features include undoped silicon.

According to one embodiment, a semiconductor device includes a substrate, a first transistor, a second transistor, a first insulating portion, and a second insulating portion. The first transistor includes a first diffusion region and a second diffusion region, a first gate insulating film, and a first gate electrode. The second transistor includes a third diffusion region and a fourth diffusion region, a second gate insulating film, and a second gate electrode. The first insulating portion is positioned between the first gate electrode and the second gate electrode. The second insulating portion covers the first transistor, the second transistor, and the first insulating portion from a side opposite to the substrate. The first insulating portion and the second insulating portion are formed of different materials.

A semiconductor device includes a substrate, a metal gate and a poly gate. The substrate includes a first region and a second region. The metal gate is disposed on the first region of the substrate. The poly gate is disposed on the second region of the substrate. A gate area of the poly gate is greater than that of the metal gate.

A semiconductor device includes: a substrate; source/drain patterns on the substrate; a channel pattern between the source/drain patterns, the channel pattern including a plurality of semiconductor patterns; a gate electrode between the plurality of semiconductor patterns; an upper separation structure extending in a first direction and spaced apart from the gate electrode in a second direction intersecting the first direction; a first backside separation structure penetrating the substrate below the gate electrode in a third direction intersecting the first direction and the second direction; and a second backside separation structure penetrating the substrate and overlapping the upper separation structure in the third direction.

A variety of applications can include memory devices implementing CMOS devices in the periphery to the memory array of the memory devices and in sense amplifiers to the memory array. The CMOS devices can include a gate structure having a dielectric sidewall with an oxide sidewall on and contacting the dielectric sidewall and with a stress liner on and contacting the oxide sidewall. The oxide sidewall can be larger than the dielectric sidewall. In fabrication of the CM OS devices, a dielectric such as a nitride can be implemented as outer material that is sacrificial, while an oxide sidewall is maintained such that the spacer between the gates of the CMOS devices and the stress liner in the periphery is substantially the oxide sidewall.

A 3D semiconductor device, the device including: a first level including a first single crystal layer and including first transistors each of which includes a single crystal channel; a first metal layer; a second metal layer overlaying the first metal layer; a second level including second transistors and overlaying the second metal layer, each of first memory cells include at least one second transistor; a third level including third transistors and overlaying the second level; a fourth level including fourth transistors and overlaying the third level, each of second memory cells include at least one fourth transistor, where at least one of the second transistors includes a metal gate, where the first level includes memory control circuits which control writing to the second memory cells, and at least one of the second transistors includes a hafnium oxide gate dielectric.

A semiconductor device may include an active pattern on a substrate, first to third gate electrodes on the active pattern, a first source/drain region and a first source/drain contact between the first and second gate electrodes, a second source/drain region and a second source/drain contact between the second and third gate electrodes, a gate spacer on both sidewalls of the second gate electrode, a first interlayer insulating layer covering the first and second source/drain regions, and a second interlayer insulating layer in contact with at least a portion of sidewalls of the first source/drain contact. A lower surface of the second interlayer insulating layer may contact upper surfaces of the second gate electrode, the second source/drain contact, and the gate spacer between the second gate electrode and the second source/drain contact.

A semiconductor device includes: a lower transistor including a lower channel structure and a lower source/drain structure on the lower channel structure; and an upper transistor above the lower transistor, the upper transistor including an upper channel structure and an upper source/drain structure on the upper channel structure, wherein a portion of the upper channel structure overlaps the lower channel structure in a vertical direction, and another portion of the upper channel structure does not overlap the lower channel structure in the vertical direction.