Conformal titanium silicon nitride-based thin films and methods of forming same
The disclosed technology generally relates to forming a titanium nitride-based thin films, and more particularly to a conformal and smooth titanium nitride-based thin films and methods of forming the same. In one aspect, a method comprises forming a diffusion barrier comprising TiSiN having a modulus exceeding 290 GPa and a Si content exceeding 2.7 atomic % by exposing a semiconductor substrate to one or more first deposition phases alternating with one or more second deposition phases. Exposing the semiconductor substrate to the one or more first deposition phases comprises alternatingly exposing the semiconductor substrate to a titanium (Ti) precursor and a nitrogen (N) precursor. Exposing the semiconductor substrate to the one or more second deposition phases comprises sequentially exposing the semiconductor substrate to the Ti precursor, followed by a silicon (Si) precursor, followed by the N precursor.
1. A method of forming a diffusion barrier, the method comprising:
forming the diffusion barrier comprising TiSiN by exposing a semiconductor substrate to one or more first deposition phases alternating with one or more second deposition phases, the diffusion barrier having one or more of:
a modulus exceeding 290 GPa and a Si content exceeding 2.7 atomic %,
a hardness exceeding 20 GPa and a Si content exceeding 2.7 atomic %,
a crystalline texture such that a grazing incidence X-ray diffraction spectrum of the diffusion barrier exhibits a ratio of an area of under a (002) peak and a sum of areas under (111) and (222) peaks exceeding 0.4 and a Si content exceeding 2.7 atomic %, or
a nanocrystalline structure having an average grain size that is less than about 6.5 nm and a Si content exceeding 2.7%,
wherein exposing the semiconductor substrate to the one or more first deposition phases comprises alternatingly exposing the semiconductor substrate to a titanium (Ti) precursor and a nitrogen (N) precursor, and
wherein exposing the semiconductor substrate to the one or more second deposition phases comprises sequentially exposing the semiconductor substrate to the Ti precursor, followed by a silicon (Si) precursor, followed by the N precursor.
2. The method of claim 1 , wherein the diffusion barrier has the Si content of 2.7-9 atomic %.
3. The method of claim 1 , wherein the diffusion barrier has the Si content of 2.7-7 atomic %.
4. The method of claim 1 , wherein the diffusion barrier has a modulus of 290-350 GPa.
5. The method of claim 1 , wherein the diffusion barrier has a hardness of 20-40 GPa.
6. The method of claim 1 , wherein the diffusion barrier has a crystalline texture such that a grazing incidence X-ray spectrum exhibits a ratio of an area of under a (002) peak and a sum of areas under (111) and (222) peaks of 0.4-4.5.
7. The method of claim 1 , wherein the diffusion barrier has a nanocrystalline structure having an average grain size of about 5.0-6.5 nm.
8. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more second deposition phases comprises sequentially exposing the semiconductor substrate to the Ti precursor and the Si precursor without an intervening exposure to the N precursor therebetween, followed by exposing the semiconductor substrate to the N precursor.
9. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more second deposition phases comprises sequentially exposing the semiconductor substrate to the Ti precursor as a first precursor, followed by the Si precursor, followed by the N precursor as a last precursor.
10. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more second deposition phases comprises exposing the semiconductor substrate to the Ti precursor for a Ti precursor exposure duration, followed by the Si precursor for a Si precursor exposure duration, followed by the N precursor, and wherein a ratio of the Ti precursor exposure duration to the Si precursor exposure duration is greater than 0to 1.
11. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more second deposition phases comprises exposing the semiconductor substrate to the Ti precursor for a Ti precursor exposure duration of greater than 0to 1 sec., followed by the Si precursor for a Si precursor exposure duration of 1-10 sec.
12. The method of claim 1 , wherein a ratio of a number of the one or more first deposition phases to a number of the one or more second deposition phases is greater than 10.
13. The method of claim 1 , wherein a ratio of a number of the one or more first deposition phases to a number of the one or more second deposition phases is 10-50.
14. The method of claim 1 , wherein the semiconductor substrate comprises an opening having an aspect ratio exceeding 5, and wherein forming the diffusion barrier comprises lining surfaces of the opening such that a ratio of a thickness of the diffusion barrier formed on a lower 25% of a height of the opening of a thickness of the diffusion barrier formed on an upper 25% of the height of the opening exceeds 0.80.
15. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more first deposition phases comprises exposing the semiconductor substrate to the N precursor as a last precursor.
16. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more second deposition phases comprises exposing the semiconductor substrate to the Ti precursor as a first precursor.
17. The method of claim 1 , wherein an exposure of the semiconductor substrate to the Ti precursor as a first precursor of the one or more second deposition phases immediately follows an exposure of the semiconductor substrate to the N precursor as a last precursor of the one or more first deposition phases without an intervening exposure to the N precursor.
18. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more first deposition phases and the one or more second deposition phases comprises exposing at a pressure in a reaction chamber greater than 1 torr.
19. The method of claim 1 , wherein the semiconductor substrate comprises a surface topography such that a ratio of a surface area of the semiconductor substrate exposed to the one or more first deposition phases and the one or more second deposition phases to a surface area of a corresponding unpatterned semiconductor substrate exceeds 2.
20. The method of claim 19 , wherein the surface topography comprises a plurality of trenches or vias having an aspect ratio exceeding 5.
21. The method of claim 20 , wherein a number and dimensions of the plurality of trenches or vias is such that the ratio of the surface areas exceeds 20.
22. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more first deposition phases and the one or more second deposition phases comprises exposing at a pressure in a reaction chamber of 3-10 torr.
23. The method of claim 1 , wherein a ratio of a number of the one or more first deposition phases to a number of the one or more second deposition phases is such that the diffusion barrier is at least partially amorphous.
24. The method of claim 1 , wherein the Si precursor is a compound selected from the group consisting of SiH 4 , Si 2 H 6 , SiH 2 Cl 2 , SiH 3 Cl, Si 2 Cl 6 and Si 3 Cl 8 .
25. The method of claim 1 , wherein the Ti precursor comprises TiCl 4 .
26. The method of claim 1 , wherein the N precursor comprises NH 3 .
27. The method of claim 1 , wherein exposing the semiconductor substrate to the one or more first deposition phases and the one or more second deposition phases is performed at a substrate temperature of 400° C. to 600° C.
28. The method of claim 1 , wherein a number of the one or more first deposition phases and a number of the one or more second deposition phases are such that the diffusion barrier layer is substantially homogenous in a layer depth direction.
29. The method of claim 1 , wherein the semiconductor substrate comprises a plurality of openings formed thereon, wherein the openings comprise a dielectric sidewall surface and an aspect ratio exceeding 5, and wherein forming the diffusion barrier comprises lining surfaces of the openings.
30. The method of claim 29 , wherein lining the surfaces of the openings comprises conformally lining such that a ratio of a thickness of the diffusion barrier layer formed on a lower 25% of a height of the openings to a thickness of the diffusion barrier layer formed on an upper 25% of the height of the openings exceeds 0.8.
31. The method of claim 30 , wherein a number and dimensions of the openings is such that a ratio of a surface area of the semiconductor substrate exposed to the one or more first deposition phases and the one or more second deposition phases to a surface area of a corresponding unpatterned semiconductor substrate exceeds 2.
32. The method of claim 30 , wherein lining the surfaces of openings comprises exposing the semiconductor substrate to the one or more first deposition phases and the one or more second deposition phases at a pressure in a reaction chamber of 3-10 torr.
33. The method of claim 30 , wherein the openings further comprise an exposed semiconductor bottom surface.