Field effect transistor devices having gate contacts formed in active region overlapping source/drain contacts
Semiconductor devices and methods are provided to fabricate FET devices having overlapping gate and source/drain contacts while preventing electrical shorts between the overlapping gate and source/drain contacts. For example, a semiconductor device includes a FET device, a vertical source/drain contact, a source/drain contact capping layer, and a vertical gate contact. The FET device includes a source/drain layer, and a gate structure. The vertical source/drain contact is formed in contact with a source/drain layer of the FET device. The source/drain contact capping layer is formed on an upper surface of the vertical source/drain contact. The vertical gate contact is formed in contact with a gate electrode layer of the gate structure. A portion of the vertical gate contact overlaps a portion of the vertical source/drain contact, wherein the source/drain contact capping layer electrically insulates the overlapping portions of the vertical gate and source/drain contacts.
1. A semiconductor device, comprising:
a field effect transistor (FET) device disposed on a semiconductor substrate, wherein the FET device comprises a source/drain layer, and a gate structure comprising a gate electrode layer, a gate capping layer disposed on an upper surface of the gate electrode layer, and a gate sidewall spacer disposed on a sidewall surface of the gate electrode layer;
a vertical source/drain contact disposed in contact with the source/drain layer of the FET device, wherein the vertical source/drain contact is disposed in a first dielectric layer;
a source/drain contact capping layer disposed on an upper recessed surface of the vertical source/drain contact, wherein upper surfaces of the source/drain capping layer, the gate capping layer and the first dielectric layer are coplanar;
a second dielectric layer disposed on the upper surfaces of the first dielectric layer, the source/drain contact capping layer, and the gate capping layer;
a vertical gate contact disposed in contact with portions of the upper surfaces of the source/drain capping layer and the gate electrode layer, which are exposed through an etched opening in the second dielectric layer and the gate capping layer, wherein a portion of the vertical gate contact overlaps a portion of the vertical source/drain contact, and wherein the source/drain contact capping layer electrically insulates the overlapping portions of the vertical gate contact and the vertical source/drain contact; and
a source/drain via contact disposed in contact with a portion of the vertical source/drain contact that is exposed through an etched opening in the source/drain contact capping layer, wherein a portion of the source/drain via contact overlaps a portion of the gate structure, and is electrically insulated from the gate electrode layer by the gate capping layer and the gate sidewall spacer;
wherein the vertical gate contact and the source/drain via contact are separate contacts that are disposed in a same metallization level and are offset from each other.
2. The semiconductor device of claim 1 , wherein the gate capping layer and the source/drain contact capping layer are formed of materials that have etch selectivity with respect to each other.
3. The semiconductor device of claim 2 , wherein the gate capping layer is formed of one of silicon nitride (SiN) and silicon boron carbon nitride (SiBCN), and wherein the source/drain contact capping layer is formed of silicon oxycarbide (SiCO).
4. The semiconductor device of claim 1 , wherein the source/drain contact capping is formed of a material which has etch selectivity with respect to materials of the gate capping layer and the gate sidewall spacer.
5. The semiconductor device of claim 4 , wherein the source/drain contact capping layer is formed of silicon oxycarbide (SiCO), wherein the gate capping layer is formed of silicon nitride (SiN), and wherein the gate sidewall spacer is formed of silicon boron carbon nitride (SiBCN).
6. The semiconductor device of claim 1 , wherein an upper surface of the source/drain via contact is coplanar with an upper surface of the vertical gate contact.
7. The semiconductor device of claim 1 , wherein the vertical source/drain contact and the vertical gate contact are formed of tungsten.
8. A semiconductor device, comprising:
a field effect transistor (FET) device disposed on a semiconductor substrate, wherein the FET device comprises vertical semiconductor fin; a source/drain layer, and a gate structure disposed over a portion of the vertical semiconductor fin, the gate structure comprising a gate electrode layer, a gate capping layer disposed on an upper surface of the gate electrode layer, and a gate sidewall spacer disposed on a sidewall surface of the gate electrode layer;
a first interlevel dielectric (ILD) layer which encapsulates the FET device;
a vertical source/drain contact disposed within the first ILD layer and in contact with the source/drain layer of the FET device and the gate sidewall spacer;
a source/drain contact capping layer disposed on an upper recessed surface of the vertical source/drain contact, wherein upper surfaces of the source/drain capping layer, the gate capping layer and the first dielectric layer are coplanar;
a second ILD layer disposed on the upper surfaces of the first ILD layer, the source/drain contact capping layer, and the gate capping layer, wherein the second ILD layer is formed of a material which comprises etch selectivity with respect to the source/drain contact capping layer; and
a vertical gate contact disposed in contact with portions of the upper surfaces of the source/drain capping layer and the gate electrode layer, which are exposed through an etched opening in the second ILD layer and the gate capping layer, wherein a portion of the vertical gate contact overlaps a portion of the vertical source/drain contact, and wherein the source/drain contact capping layer electrically insulates the overlapping portions of the vertical gate contact and the vertical source/drain contact; and
a source/drain via contact disposed in contact with a portion of the vertical source/drain contact that is exposed through an etched opening in the source/drain contact capping layer, wherein a portion of the source/drain via contact overlaps a portion of the gate structure, and is electrically insulated from the gate electrode layer by the gate capping layer and the gate sidewall spacer;
wherein the vertical gate contact and the source/drain via contact are separate contacts that are disposed in a same metallization level and are offset from each other.
9. The semiconductor device of claim 8 , wherein the gate capping layer and the source/drain contact capping layer are formed of materials that have etch selectivity with respect to each other.
10. The semiconductor device of claim 9 , wherein the gate capping layer is formed of one of silicon nitride (SiN) and silicon boron carbon nitride (SiBCN), and wherein the source/drain contact capping layer is formed of silicon oxycarbide (SiCO).
11. The semiconductor device of claim 8 , wherein the source/drain contact capping is formed of a material which has etch selectivity with respect to materials of the gate capping layer and the gate sidewall spacer.
12. The semiconductor device of claim 11 , wherein the source/drain contact capping layer is formed of silicon oxycarbide (SiCO), wherein the gate capping layer is formed of silicon nitride (SiN), and wherein the gate sidewall spacer is formed of silicon boron carbon nitride (SiBCN).
13. The semiconductor device of claim 8 , wherein an upper surface of the source/drain via contact is coplanar with an upper surface of the vertical gate contact.
14. The semiconductor device of claim 8 , wherein the vertical source/drain contact and the vertical gate contact are formed of tungsten.
15. The semiconductor device of claim 8 , wherein the FET device comprises a FinFET device.