Isolation structure for preventing unintentional merging of epitaxially grown source/drain
A semiconductor device includes a first active region and a second active region disposed over a substrate. A first source/drain component is grown on the first active region. A second source/drain component is grown on the second active region. An interlayer dielectric (ILD) is disposed around the first source/drain component and the second source/drain component. An isolation structure extends vertically through the ILD. The isolation structure separates the first source/drain component from the second source/drain component.
1. A device, comprising:
a first active region and a second active region disposed over a substrate;
a first source/drain component grown on the first active region;
a second source/drain component grown on the second active region;
an interlayer dielectric (ILD) disposed around the first source/drain component and the second source/drain component; and
an isolation structure extending vertically through the ILD and separating the first source/drain component from the second source/drain component, wherein an uppermost surface of the isolation structure is more elevated vertically than an uppermost surface of the first source/drain component.
2. The device of claim 1 , wherein the first source/drain component and the second source/drain component each has an asymmetrical profile in a cross-sectional view.
3. The device of claim 2 , wherein:
The first source/drain component and the second source/drain component each has a first outermost portion in a first horizontal side and a second outermost portion in a second horizontal side opposite the first horizontal side; and
a shape of the first outermost portion is different than a shape of the second outermost portion.
4. The device of claim 3 , wherein:
the shape of the first outermost portion resembles a line; and
the shape of the second outermost portion resembles a pointy tip.
5. The device of claim 1 , wherein at least one of the first source/drain component and the second source/drain component includes multiple epitaxially source/drain features that are merged together.
6. The device of claim 1 , wherein the isolation structure includes:
a dielectric liner that is in direct contact with the first source/drain component and the second source/drain component; and
a dielectric segment disposed over the dielectric liner.
7. The device of claim 6 , wherein the dielectric liner and the dielectric segment have different material compositions.
8. The device of claim 1 , wherein the device is a FinFET device.
9. The device of claim 1 , wherein the device is a Gate-All-Around (GAA) device.
10. A device, comprising:
a plurality of active regions disposed over a substrate;
a plurality of gate structures disposed over the active regions; and
a plurality of source/drains epitaxially grown over the active regions, respectively, wherein in a cross-sectional view defined by a horizontal axis and a vertical axis, at least a first source/drain of the plurality of the source/drains includes a first outermost portion having a flat edge and a second outermost portion having a protruding tip, wherein the first outermost portion and the second outermost portion are outermost portions that extend in opposite directions along the horizontal axis.
11. The device of claim 10 , further comprising an isolation structure disposed between the first source/drain and a second source/drain of the plurality of the source/drains, wherein an uppermost surface of the isolation structure is more elevated vertically than an uppermost surface of the first source/drain.
12. A method, comprising:
forming a first active region and a second active region over a substrate;
epitaxially growing a first source/drain component and a second source/drain component over the first active region and the second active region, respectively;
forming a material layer over the first source/drain component and the second source/drain component;
etching an opening through the material layer, wherein the opening separates the first source/drain component from the second source/drain component; and
filling the opening with one or more dielectric materials.
13. The method of claim 12 , wherein the first source/drain component and the second source/drain component merge into each other after the epitaxially growing.
14. The method of claim 12 , wherein the filling the opening includes filling the opening with a single type of dielectric material.
15. The method of claim 12 , wherein the filling the opening includes:
depositing a dielectric liner in the opening, wherein the dielectric liner partially fills the opening; and
depositing a dielectric material over the dielectric liner, wherein the dielectric material completely fills the opening.
16. The method of claim 12 , wherein the forming the material layer includes forming a sacrificial layer as the material layer, and wherein the method further includes:
removing the sacrificial layer after the opening has been etched in the sacrificial layer;
after the sacrificial layer has been removed, forming an interlayer dielectric (ILD) over and around the first source/drain component and the second source/drain component;
after the ILD has been formed, forming a metal-containing gate structure over the substrate; and
after the forming of the metal-containing gate structure, forming a first source/drain contact over the first source/drain component and forming a second source/drain contact over the second source/drain component.
17. The method of claim 16 , wherein the forming the sacrificial layer includes forming a photoresist layer as the sacrificial layer.
18. The method of claim 12 , wherein the forming the material layer includes forming an interlayer dielectric (ILD) as the material layer, and wherein the method further includes:
after the filling of the opening, forming a metal-containing gate structure over the substrate; and
after the forming of the metal-containing gate structure, forming a first source/drain contact over the first source/drain component and forming a second source/drain contact over the second source/drain component.
19. The method of claim 12 , wherein the forming the material layer includes forming an interlayer dielectric (ILD) as the material layer, and wherein the method further includes:
before the etching of the opening, forming a metal-containing gate structure over the substrate; and
after the filling the opening with the one or more dielectric materials, forming a first source/drain contact over the first source/drain component and forming a second source/drain contact over the second source/drain component.
20. The method of claim 12 , wherein the forming the material layer includes forming an interlayer dielectric (ILD) as the material layer, and wherein the method further includes, before the etching of the opening:
forming a metal-containing gate structure over the substrate; and
forming a first source/drain contact over the first source/drain component and forming a second source/drain contact over the second source/drain component;
wherein the etching of the opening is performed after the first source/drain contact and the second source/drain contact have been formed.