Self-aligned contacts
View Patent ↗A method of forming a gate structure with a self-aligned contact is provided and includes sequentially depositing a sacrificial layer and a secondary layer onto poly-Si disposed at a location of the gate structure, encapsulating the sacrificial layer, the secondary layer and the poly-Si, removing the sacrificial layer through openings formed in the secondary layer and forming silicide within at least the space formally occupied by the sacrificial layer.
1. A method of forming a gate structure with a self-aligned contact, the method comprising:
sequentially depositing a sacrificial layer and a secondary layer onto poly-Si layer disposed at a location of the gate structure;
encapsulating the sacrificial layer, the secondary layer and the poly-Si layer;
removing the sacrificial layer through openings formed in the secondary layer; and
forming silicide within at least the space formally occupied by the sacrificial layer.
2. The method according to claim 1 , further comprising forming additional silicide at source and drain regions relative to the gate structure.
3. The method according to claim 2 , wherein the forming of the silicide and the forming of the additional silicide are decoupled from one another.
4. The method according to claim 2 , further comprising depositing an insulator onto the secondary layer and the additional silicide.
5. The method according to claim 4 , further comprising:
opening contact holes at the source and drain regions; and
filling the opened contact holes with contact via material.
6. The method according to claim 1 , wherein the sacrificial layer comprises germanium.
7. The method according to claim 1 , wherein the secondary layer comprises silicon nitride.
8. The method according to claim 1 , wherein the encapsulating comprises forming spacers.
9. The method according to claim 1 , further comprising forming the openings by lithography.
10. The method according to claim 9 , wherein a minimum distance between the openings satisfies an aspect ratio requirement of the silicide forming operation.
11. The method according to claim 1 , wherein the removing comprises etching of the sacrificial layer.
12. The method according to claim 1 , wherein the forming of the silicide comprises:
depositing silicide forming material by at least one of atomic layer deposition (ALD) and chemical vapor deposition (CVD) in the space formally occupied by the sacrificial layer; and
annealing the silicide forming material to generate the silicide.
13. The method according to claim 12 , wherein the silicide forming material comprises at least one of tungsten (W), platinum (Pt), titanium (Ti), cobalt (Co), nickel (NI) and tantalum (Ta).
14. The method according to claim 12 , further comprising removing excess silicide forming material through the openings.