Methods of forming reacted conductive gate electrodes
A semiconductor device and a method for fabricating a semiconductor device involve a semiconductor layer that includes a first material and a second material. The first and second materials can be silicon and germanium. A contact of the device has a portion proximal to the semiconductor layer and a portion distal to the semiconductor layer. The distal portion includes the first material and the second material. A metal layer formed adjacent to the relaxed semiconductor layer and adjacent to the distal portion of the contact is simultaneously reacted with the relaxed semiconductor layer and with the distal portion of the contact to provide metallic contact material.
1. A method for forming a semiconductor device, the method comprising:
providing a substrate;
forming a gate dielectric layer over a portion of the substrate, thereby defining a channel below the gate dielectric layer;
forming a source contact and a drain contact proximate the channel by depositing a metallic material and performing an annealing step, each of the source contact and drain contact comprising a reacted conductive silicide layer, the reacted conductive silicide layer comprising silicon, germanium, and the metallic material; and
forming a gate contact over at least a portion of the gate dielectric layer by depositing the metallic material and performing an annealing step, the gate contact including a reacted conductive silicide portion comprising a semiconductor material and the metallic material,
wherein the channel of the semiconductor device is strained.
2. The method of claim 1 , wherein the reacted conductive silicide layer of at least one of the source contact and drain contact is formed proximate a material comprising SiGe.
3. The method of claim 2 , further comprising defining an isolation region proximate the material comprising SiGe.
4. The method of claim 2 , wherein the SiGe is at least partially relaxed.
5. The method of claim 1 , wherein the reacted conductive silicide portion of the gate contact comprises germanium.
6. The method of claim 1 , wherein the gate contact comprises an unreacted semiconductor portion.
7. The method of claim 6 , wherein the unreacted semiconductor portion consists essentially of polycrystalline silicon.
8. The method of claim 6 , wherein the unreacted semiconductor portion comprises germanium.
9. The method of claim 1 , further comprising forming a strain-inducing material over at least a portion of the substrate, the strain-inducing material comprising silicon, wherein strain in the strained channel is induced by the strain-inducing material.
10. The method of claim 9 , wherein forming the strain-inducing material comprises epitaxial growth.
11. The method of claim 9 , further comprising defining an isolation region, wherein the isolation region is disposed proximate the strain-inducing material.
12. The method of claim 1 , further comprising forming a strain-inducing material over at least a portion of the substrate, the strain-inducing material comprising germanium, wherein strain in the strained channel is induced by the strain-inducing material.
13. The method of claim 12 , wherein forming the strain-inducing material comprises epitaxial growth.
14. The method of claim 12 , further comprising defining an isolation region, wherein the isolation region is disposed proximate the strain-inducing material.
15. The method of claim 12 , wherein the strain-inducing material is at least partially relaxed.
16. The method of claim 1 , wherein the metallic material comprises at least one of nickel, platinum, and zirconium.
17. The method of claim 1 , wherein the strained channel comprises at least one of silicon and germanium.
18. The method of claim 1 , wherein the strained channel is disposed proximate a material comprising SiGe.
19. The method of claim 1 , wherein the strained channel is tensilely strained.
20. The method of claim 1 , wherein the strained channel is compressively strained.
21. The method of claim 1 , wherein the gate dielectric layer comprises at least one of silicon oxynitride and a high-k dielectric.
22. The method of claim 1 , wherein forming the gate dielectric layer comprises at least one of oxidation and deposition.
23. The method of claim 1 , wherein the strained channel is disposed over an insulator layer.
24. The method of claim 1 , wherein the strained channel is disposed over a relaxed material.
25. The method of claim 16 , wherein the metallic material comprises nickel.
26. The method of claim 25 , wherein the metallic material consists essentially of nickel.
27. The method of claim 26 , wherein the strained channel comprises silicon.
28. The method of claim 27 , wherein the strained channel is compressively strained.
29. The method of claim 27 , wherein the strained channel consists essentially of silicon.
30. The method of claim 29 , wherein the strained channel is compressively strained.
31. The method of claim 29 , further comprising forming a strain-inducing material over at least a portion of the substrate, the strain-inducing material consisting essentially of SiGe, wherein strain in the strained channel is induced by the strain-inducing material.
32. The method of claim 31 , wherein the strain-inducing material is disposed proximate the reacted conductive silicide layer and the strained channel.
33. The method of claim 32 , wherein forming the strain-inducing material comprises epitaxial growth.
34. The method of claim 33 , wherein the substrate consists essentially of one or more semiconductor materials.
35. The method of claim 34 , wherein the substrate consists essentially of silicon.
36. The method of claim 35 , further comprising defining an isolation region, wherein the strain-inducing material is disposed proximate the isolation region.
37. The method of claim 36 , wherein the semiconductor device is a p-channel MOSFET.
38. The method of claim 37 , wherein the strained channel is compressively strained.
39. The method of claim 33 , wherein the strained channel is disposed over an insulator layer.
40. The method of claim 39 , further comprising defining an isolation region, wherein the strain-inducing material is disposed proximate the isolation region.
41. The method of claim 40 , wherein the semiconductor device is a p-channel MOSFET.
42. The method of claim 41 , wherein the strained channel is compressively strained.