Titanium silicon nitride barrier layer
The disclosed technology generally relates to a barrier layer comprising titanium silicon nitride, and more particularly to a barrier layer for nonvolatile memory devices, and methods of forming the same. In one aspect, a method of forming an electrode for a phase change memory device comprises forming over a semiconductor substrate an electrode comprising titanium silicon nitride (TiSiN) on a phase change storage element configured to store a memory state. Forming the electrode comprises exposing a semiconductor substrate to one or more cyclical vapor deposition cycles, wherein a plurality of the cyclical vapor deposition cycles comprises an exposure to a Ti precursor, an exposure to a N precursor and an exposure to a Si precursor.
1. A method of forming a diffusion barrier for an integrated circuit device, the method comprising:
forming the diffusion barrier comprising TiSiN without aid of a plasma by exposing a substrate to one or more vapor deposition cycles, each of the vapor deposition cycles comprising alternating exposures to one or more first deposition phases followed by one or more second deposition phases,
wherein each of the one or more first deposition phases comprises sequential exposures of the substrate to a titanium (Ti) precursor comprising TiCl 4 alternating with a nitrogen (N) precursor,
wherein each of the one or more second deposition phases comprises sequential exposures of the substrate to a silicon (Si) precursor alternating with a N precursor, and
wherein in at least one of the first deposition phases, the exposure to the N precursor follows the exposure to the Ti precursor without an intervening exposure to the Si precursor.
2. The method of claim 1 , wherein forming the diffusion barrier comprises exposing the substrate to one or more vapor deposition cycles at a temperature lower than 400° C.
3. The method of claim 1 , wherein forming the diffusion barrier comprises exposing the substrate to the one or more vapor deposition cycles at a temperature greater than 200° C. and less than 400° C.
4. The method of claim 1 , wherein the diffusion barrier is at least partially amorphous.
5. The method of claim 1 , wherein forming the diffusion barrier comprises adjusting a silicon concentration such that the diffusion barrier has an electrical resistivity between about 500 μΩ-cm and about 30,000 μΩ-cm.
6. The method of claim 1 , wherein the diffusion barrier has a silicon concentration exceeding about 5 atomic %.
7. The method of claim 1 , wherein the Si precursor is a precursor 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 .
8. The method of claim 1 , wherein the substrate comprises a via or a trench formed through an insulating layer, and wherein forming the diffusion barrier comprises filling the via or the trench with successively grown conformal TiSiN layers.
9. The method of claim 1 , wherein at least some of the first deposition phases locally forms TiN.
10. The method of claim 9 , wherein forming the diffusion barrier layer comprises forming by thermal atomic layer deposition without aid of a plasma.
11. The method of claim 9 , wherein the Si precursor is a precursor 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 .
12. The method of claim 9 , wherein exposing the substrate to the one or more vapor deposition cycles comprises:
exposing the substrate to one or more first deposition phases each comprising the exposure to the Ti precursor and the exposure to the N precursor; and
exposing the substrate to one or more second deposition phases each comprising the exposure to the Si precursor.
13. The method of claim 12 , wherein each of the second deposition phases further comprises a further exposure to the N precursor.
14. The method of claim 12 , wherein at least some of the first deposition phases locally forms TiN.
15. The method of claim 12 , wherein at least some of the second deposition phases locally forms SiN.
16. The method of claim 1 , wherein at least some of the second deposition phases locally forms SiN.
17. A method of forming an integrated circuit structure, the method comprising:
forming a diffusion barrier layer over a substrate, the diffusion barrier layer comprising titanium silicon nitride (TiSiN), at a temperature between 200° C. and 390° C. by exposing the substrate to one or more vapor deposition cycles, wherein each of the one or more vapor deposition cycles comprises an exposure to a titanium (Ti) precursor comprising TiCl 4 , an exposure to a nitrogen (N) precursor and an exposure to a silicon (Si) precursor,
wherein the exposure to the N precursor follows the exposure to the Ti precursor without an intervening exposure to the Si precursor; and
forming a metallization line on the diffusion barrier layer.
18. The method of claim 17 , wherein the substrate comprises a trench, and wherein forming the diffusion barrier layer comprises lining the trench with the diffusion barrier layer.
19. The method of claim 17 , wherein the metallization line comprises a wordline for a nonvolatile memory device.