Semiconductor structure and forming method thereof
Semiconductor structure and forming method thereof are provided. The forming method includes: providing a substrate; forming a plurality of initial composite layers on a portion of the substrate; forming a plurality of source and drain layers on surfaces of the plurality of channel layers exposed by a first opening and grooves by using a selective epitaxial growth process, the plurality of source and drain layers being parallel to a first direction and distributed along a second direction, the second direction being parallel to a normal direction of the substrate, and gaps being between adjacent source and drain layers; forming contact layers on surfaces of the plurality of source and drain layers and in the gaps; and forming a conductive structure on a surface of a contact layer on a source and drain layer of the plurality of source and drain layers.
1 . A semiconductor structure, comprising:
a substrate; and
a composite layer over the substrate, the composite layer including a plurality of channel layers and at least one structure layer, and one of the at least one structure layer including:
a first gate structure,
inner sidewall spacers on both sides of the first gate structure,
a source layer and a drain layer on each side of the inner sidewall spacer, and
a contact layer contained within each of the source layer and the drain layer,
wherein:
the first gate structure, the inner sidewall spacers, a first portion of each of the source layer and the drain layer, and a first portion of the contact layer together are formed between adjacent channel layers of the plurality of channel layers and together have an orthographic projection overlapping with the adjacent channel layers along a vertical direction.
2 . The structure according to claim 1 , further comprising an insulating dielectric layer formed between the substrate and the composite layer.
3 . The structure according to claim 1 , wherein
the first portion of each of the source layer and the drain layer extends outside a corresponding sidewall of the channel layer.
4 . The structure according to claim 1 , wherein
the first portion of each of the source layer and the drain layer encapsulates a corresponding sidewall and surface portions of the channel layer that are connected to the corresponding sidewall.
5 . The structure according to claim 1 , wherein
the first portion of the contact layer extends outside a corresponding sidewall of the channel layer.
6 . The structure according to claim 1 , wherein
the first portion of the contact layer is located in a middle section of the source layer and the drain layer along the vertical direction.
7 . The structure according to claim 1 , further comprising:
a second gate structure, gate sidewall spacers, and dielectric spacers, that are formed on a top channel layer of the plurality of channel layers, wherein
the gate sidewall spacers are on both sides of the second gate structure,
the dielectric spacers are on sidewalls of the gate sidewall spacers and on the both sides of the second gate structure.
8 . The structure according to claim 7 , wherein
top surfaces of the dielectric spacers are coplanar with a top surface of the second gate structure, and
outer side surfaces of the dielectric spacers are coplanar with sidewall surfaces of the plurality of channel layers.
9 . The structure according to claim 7 , wherein
a second portion of each of the source layer and the drain layer is formed on a lower portion of an outer side surface of a corresponding dielectric spacer.
10 . The structure according to claim 9 , further comprising:
an interlayer dielectric layer formed on top of the second portion of each of the source layer and the drain layer, wherein the interlayer dielectric layer is further formed on an upper portion of the outer side surface of the corresponding dielectric spacer.
11 . The structure according to claim 1 , further comprising:
a shared source/drain layer and a conductive structure formed over the shared source/drain layer, wherein
a second portion of the contact layer is formed between the shared source/drain layer and the conductive structure.
12 . The structure according to claim 2 , wherein
another one of the at least one structure layer is formed between the insulating dielectric layer and a bottom channel layer of the plurality of channel layers, and
the contact layer of the another one of the at least one structure layer is formed directly on surface of the insulating dielectric layer.
13 . A method for forming a semiconductor structure, comprising:
providing a substrate; and
forming a composite layer over the substrate, the composite layer including a plurality of channel layers and at least one structure layer, and one of the at least one structure layer including:
a first gate structure,
inner sidewall spacers on both sides of the first gate structure,
a source layer and a drain layer on each side of the inner sidewall spacer, and
a contact layer contained within each of the source layer and the drain layer,
wherein the first gate structure, the inner sidewall spacers, a first portion of each of the source layer and the drain layer, and a first portion of the contact layer together are formed between adjacent channel layers of the plurality of channel layers and together have an orthographic projection overlapping with the adjacent channel layers along a vertical direction.