Etch profile control of gate contact opening
A semiconductor device includes a gate structure, source/drain regions, source/drain contacts, a gate dielectric cap, an etch stop layer, and a gate contact. The gate structure is over a substrate. The source/drain regions are at opposite sides of the gate structure. The source/drain contacts are over the source/drain regions, respectively. The gate dielectric cap is over the gate structure and has opposite sidewalls interfacing the source/drain contacts.
1. A device, comprising: a gate structure over a substrate; source/drain regions at opposite sides of the gate structure; source/drain contacts over the source/drain regions, respectively; a gate dielectric cap over the gate structure and having opposite sidewalls interfacing the source/drain contacts; a nitride-based etch stop layer over the source/drain contacts and the gate dielectric cap; and a gate contact extending through the nitride-based etch stop layer and the gate dielectric cap to electrically connect with the gate structure, wherein the nitride-based etch stop layer has an oxidized region interfacing opposite sidewalls of the gate contact.
2. The device of claim 1 , wherein an interface formed by the oxidized region of the nitride-based etch stop layer and the gate contact is slant.
3. The device of claim 1 , wherein an interface formed by the oxidized region of the nitride-based etch stop layer and the gate contact is vertical.
4. The device of claim 1 , further comprising:
a metal cap between the gate dielectric cap and the gate structure.
5. The device of claim 4 , wherein the metal cap is fluorine-free tungsten.
6. The device of claim 1 , further comprising:
gate spacers spacing apart the source/drain contacts from the gate structure.
7. The device of claim 6 , wherein the gate dielectric cap is further over the gate spacers.
8. The device of claim 1 , wherein the device is a fin field-effect transistor (FinFET) or a gate-all-around (GAA) transistor.
9. A device, comprising:
a source region and a drain region over a substrate;
a channel region between the source region and the drain region;
a gate structure over the channel region;
a dielectric cap over the gate structure;
a nitride-based etch stop layer over the dielectric cap, the nitride-based etch stop layer having an oxidized region over the gate structure; and
a gate contact extending through the oxidized region of the nitride-based etch stop layer and the dielectric cap to the gate structure.
10. The device of claim 9 , wherein the nitride-based etch stop layer has an un-oxidized region over the source region.
11. The device of claim 9 , wherein the nitride-based etch stop layer has an un-oxidized region over the drain region.
12. The device of claim 9 , wherein the dielectric cap has an oxidized region below the oxidized region of the nitride-based etch stop layer.
13. The device of claim 12 , wherein the oxidized region of the dielectric cap continuously extends from the oxidized region of the nitride-based etch stop layer.
14. The device of claim 9 , further comprising:
an interlayer dielectric over the nitride-based etch stop layer, wherein an interface between the gate contact and the oxidized region of the nitride-based etch stop layer is aligned with an interface between the gate contact and the interlayer dielectric.
15. A device, comprising:
a gate structure over a substrate;
a source region and a drain region at opposite sides of the gate structure;
a source contact over the source region;
a drain contact over the drain region; and
a nitride-based etch stop layer over the gate structure, the source contact, and the drain contact, the nitride-based etch stop layer having an oxidized region over the gate structure, and an un-oxidized region over the source contact and the drain contact.
16. The device of claim 15 , wherein the oxidized region of the nitride-based etch stop layer has a smaller width than the un-oxidized region of the nitride-based etch stop layer.
17. The device of claim 15 , further comprising:
a gate contact laterally surrounded by the oxidized region of the nitride-based etch stop layer.
18. The device of claim 15 , further comprising:
a dielectric cap laterally between the source contact and the drain contact, the dielectric cap spacing apart the nitride-based etch stop layer from the gate structure.
19. The device of claim 18 , wherein the dielectric cap comprises an oxidized region over the gate structure and an un-oxidized region interfacing the source contact and the drain contact.
20. The device of claim 19 , wherein the oxidized region of the dielectric cap is directly below the oxidized region of the oxidized region of the nitride-based etch stop layer.