Integrated circuit device with source/drain barrier
Various examples of an integrated circuit device and a method for forming the device are disclosed herein. In an example, a method includes receiving a workpiece that includes a substrate, and a device fin extending above the substrate. The device fin includes a channel region. A portion of the device fin adjacent the channel region is etched, and the etching creates a source/drain recess and forms a dielectric barrier within the source/drain recess. The workpiece is cleaned such that a bottommost portion of the dielectric barrier remains within a bottommost portion of the source/drain recess. A source/drain feature is formed within the source/drain recess such that the bottommost portion of the dielectric barrier is disposed between the source/drain feature and a remainder of the device fin.
1. A device comprising:
a first fin disposed on a substrate;
a second fin disposed on the substrate adjacent the first fin;
a first source/drain feature disposed on the first fin;
a second source/drain feature disposed on the second fin, wherein the first and second source/drain features are unmerged with respect to each other;
a first dielectric barrier layer disposed under and interfacing with the first source/drain feature, wherein the first dielectric barrier layer includes remnants selected from the group consisting of an etchant, a photoresist material and the first fin; and
a second dielectric barrier layer disposed under and interfacing with the second source/drain feature, wherein the second dielectric barrier layer is discontinuous with respect to the first dielectric barrier layer.
2. The device of claim 1 , wherein the first fin defines a first channel region and the first source/drain feature interfaces with the first channel region.
3. The device of claim 2 , wherein the thickness of the first dielectric barrier layer changes as the first dielectric barrier layer extends towards the first channel region.
4. The device of claim 2 , wherein the first fin further defines a second channel region,
wherein the first source/drain feature interfaces with the second channel region, and
wherein the first dielectric barrier layer extends continuously from the first channel region to the second channel region.
5. The device of claim 1 , further comprising a dielectric isolation structure disposed on the substrate, the dielectric isolation structure having a first portion disposed on and interfacing with a first side of the first fin and a second portion disposed on and interfacing with a second side of the first fin, the second side of the first fin being opposite the first side of the first fin, and
wherein the thickness of the first dielectric barrier layer changes as the first dielectric barrier layer extends from the first portion of the dielectric isolation structure to the second portion of the dielectric isolation structure.
6. The device of claim 1 , wherein the second dielectric barrier layer includes remnants selected from the group consisting of the etchant, the photoresist material and the second fin.
7. The device of claim 1 , further comprising a gate stack disposed on and interfacing with the first fin and the second fin.
8. A device comprising:
a first fin disposed on a substrate;
a second fin disposed on the substrate adjacent the first fin;
a first source/drain feature disposed on the first fin;
a second source/drain feature disposed on the first fin, wherein the first and second source/drain features are merged with each other;
a first dielectric barrier layer disposed under and interfacing with the first source/drain feature, wherein the first dielectric barrier layer includes remnants selected from the group consisting of an etchant, a photoresist material and the first fin; and
a second dielectric barrier layer disposed under and interfacing with the second source/drain feature.
9. The device of claim 8 , further comprising a dielectric isolation structure disposed on the substrate, wherein the first fin and the second fin are at least partially embedded in the dielectric isolation structure.
10. The device of claim 9 , wherein the dielectric isolation structure has a topmost surface positioned at a first height above the substrate and the first dielectric barrier layer has a topmost surface positioned at a second height above the substrate that is greater than the first height.
11. The device of claim 10 , wherein the first dielectric barrier layer has a bottommost surface positioned at a third height above the substrate that is less than the first height.
12. The device of claim 8 , wherein the first fin further includes a first channel region, and
wherein the first dielectric barrier layer has a first thickness under the first source/drain feature and a second thickness adjacent the first channel region of the first fin, the second thickness being different than the first thickness.
13. The device of claim 12 , wherein the second thickness is less than the first thickness.
14. The device of claim 13 , wherein the first fin further includes a second channel region,
wherein the first source/drain feature is disposed on the first fin between the first channel region and the second channel region, and
wherein the first dielectric barrier layer has a third thickness adjacent the second channel region, the third thickness is less than the first thickness.
15. The device of claim 14 , wherein the first source/drain feature interfaces with both the first channel region and the second channel region.
16. A device comprising:
a first channel region disposed over a substrate;
a first gate structure disposed on the first channel region;
a first source/drain feature disposed over the substrate and associated with the first channel region; and
a first electrically insulating layer interfacing with the first source/drain feature and the first channel region, wherein the first electrically insulating layer extends from under the first source/drain feature towards the first channel region such that the thickness of the first electrically insulating layer changes as the first electrically insulating layer extends from under the first source/drain feature towards the first channel region.
17. The device of claim 16 , wherein the first electrically insulating layer includes a germanium-containing material.
18. The device of claim 16 , wherein the first electrically insulating layer is formed of a material that includes a semiconductor material, carbon, oxygen and hydrogen, and
wherein the material has between about 0 and about 1 atomic percent of the semiconductor material, between about 30 and about 40 atomic percent carbon, between about 10 and about 20 atomic percent oxygen, and between about 20 and about 30 atomic percent hydrogen.
19. The device of claim 16 , further comprising a second channel region disposed over the substrate,
wherein the first source/drain feature is further associated with the second channel region; and
wherein the first electrically insulating layer extends continuously from the first channel region to the second channel region.
20. The device of claim 19 , wherein the thickness of the first electrically insulating layer changes as the first electrically insulating layer extends from under the first source/drain feature towards the second channel region.