NITROGEN PROFILE ENGINEERING IN NITRIDED HIGH DIELECTRIC CONSTANT FILMS

• US 20080081113A1
• Filed: 09/29/2006
• Published: 04/03/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Clark, Robert D.
• Granted Patent: US 7,767,262 B2
• Time in Patent Office: Days
• US Class Current: 427/255.394
• CPC Class Codes: C23C 16/308 Oxynitrides
• CPC Class Codes: C23C 16/45529 specially adapted for making a layer stack of alternating different compositions or gradient compositions
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions

Abstract

A method of forming a nitrided high-k film by disposing a substrate in a process chamber and forming the nitrided high-k film on the substrate by a) depositing a nitrogen-containing film, and b) depositing an oxygen-containing film, wherein steps a) and b) are performed in any order, any number of times, so as to oxidize at least a portion of the thickness of the nitrogen-containing film. The oxygen-containing film and the nitrogen-containing film contain the same one or more metal elements selected from alkaline earth elements, rare earth elements, and Group IVB elements of the Periodic Table, and optionally aluminum, silicon, or aluminum and silicon. According to one embodiment, the method includes forming a nitrided hafnium based high-k film. The nitrided high-k film can be formed by atomic layer deposition (ALD) or plasma-enhanced ALD (PEALD).

Claims

1. A method of forming a nitrided high-k film, comprising:

disposing a substrate in a process chamber; and

forming a nitrided high-k film on the substrate by;

a) depositing a nitrogen-containing film; and

b) depositing an oxygen-containing film, wherein steps a) and b) are alternatingly performed, in any order, any number of times, so as to oxidize at least a portion of the thickness of the nitrogen-containing film,

wherein the nitrogen-containing film and the oxygen-containing film comprise the same one or more metal elements selected from alkaline earth elements, rare earth elements, and Group IVB elements of the Periodic Table, and optionally aluminum, silicon, or aluminum and silicon.

2. The method of claim 1, wherein the oxidized portion of the thickness of the nitrogen-containing film comprises a variable nitrogen:

oxygen ratio.

3. The method of claim 1, wherein the forming comprises ALD or PEALD.

4. The method of claim 1, wherein the forming includes sequentially first, performing step a), and second, performing step b), so as to oxidize at least the portion of the thickness of the nitrogen-containing film during step b).

5. The method of claim 4, wherein the nitrogen:

oxygen ratio in the oxidized portion of the thickness of the nitrogen-containing film increases in the direction towards the substrate.

6. The method of claim 4, wherein the forming further comprises:

c) prior to step b), exposing the substrate to an oxygen-containing gas prior to, during, or after step a).

7. The method of claim 1, wherein the nitrogen:

oxygen ratio in the nitrided high-k film monotonically varies through the thickness thereof.

8. The method of claim 1, wherein the nitrogen-containing film and the oxygen-containing film each comprise hafnium.

9. The method of claim 1, wherein the nitrogen-containing film and the oxygen-containing film each comprise a plurality of metal elements selected from the alkaline earth elements, rare earth elements, and Group IVB elements.

10. The method of claim 1, wherein the nitrogen-containing film and the oxygen-containing film each comprise hafnium and silicon.

11. The method of claim 1, wherein the nitrogen-containing film and the oxygen-containing film each comprise hafnium and strontium.

12. The method of claim 1, wherein step a) comprises

exposing the substrate to a gas pulse sequence:

i) sequentially first, exposing the substrate to a gas pulse comprising the one or more metal elements selected from alkaline earth elements, rare earth elements, and Group IVB elements, and second, exposing the substrate to a gas pulse comprising a nitrogen-containing gas;

ii) optionally, sequentially first, exposing the substrate to a gas pulse comprising an aluminum precursor, and second, exposing the substrate to a gas pulse containing the nitrogen-containing gas; and

iii) optionally, sequentially first, exposing the substrate to a gas pulse containing a silicon precursor, and second, exposing the substrate to a gas pulse containing the nitrogen-containing gas,

wherein each of i), optionally ii), and optionally iii) are optionally repeated any number of desired times, and wherein the gas pulse sequence including i), optionally ii), and optionally iii) is optionally repeated, in any order, any number of desired times.

13. The method of claim 12, wherein the nitrogen-containing gas comprises NH₃, N₂H₄, C₁-C₁₀ alkylhydrazine compounds, plasma excited nitrogen, NO, NO₂, or N₂O, or a combination of two or more thereof.

14. The method of claim 1, wherein step b) comprises

exposing the substrate to a gas pulse sequence, in any order:

i) sequentially first, exposing the substrate to a gas pulse comprising the one or more metal elements selected from alkaline earth elements, rare earth elements, and Group IVB elements, and second, exposing the substrate to a gas pulse comprising an oxygen-containing gas;

ii) optionally, sequentially first, exposing the substrate to a gas pulse comprising an aluminum precursor, and second, exposing the substrate to a gas pulse containing the oxygen-containing gas; and

iii) optionally sequentially first, exposing the substrate to a gas pulse containing a silicon precursor, and second, exposing the substrate to a gas pulse containing the oxygen-containing gas,

wherein each of i), optionally ii), and optionally iii) are optionally repeated any number of desired times, and wherein the gas pulse sequence including i), optionally ii), and optionally iii) is optionally repeated, in any order, any number of desired times.

15. The method of claim 14, wherein the oxygen-containing gas comprises O₂, H₂O, H₂O₂, ozone, plasma excited oxygen, NO, NO₂, or N₂O, or a combination of two or more thereof.

16. The method of claim 1, further comprising:

exposing the nitrided high-k film to an oxygen-containing gas to further incorporate oxygen into the nitrided high-k film.

17. A method of forming a nitrided hafnium based high-k film, comprising:

disposing a substrate in a process chamber; and

forming a nitrided hafnium based high-k film on the substrate by;

a) depositing a nitrogen-containing film; and

b) depositing an oxygen-containing film, wherein steps a) and b) are alternatingly performed, in any order, any number of times, so as to oxidize at least a portion of the thickness of the nitrogen-containing film, and the nitrogen-containing film and the oxygen-containing film each comprise hafnium, optionally one or more additional metal elements selected from alkaline earth elements, rare earth elements, and Group IVB elements of the Periodic Table, and optionally aluminum, silicon, or aluminum and silicon.

18. The method of claim 17, wherein the oxidized portion of the thickness of the nitrogen-containing film comprises a variable nitrogen:

oxygen ratio.

19. The method of claim 17, wherein the forming includes sequentially first, performing step a), and second, performing step b), so as to oxidize at least the portion of the thickness of the nitrogen-containing film during step b).

20. The method of claim 19, wherein the nitrogen:

oxygen ratio in the oxidized portion of the thickness of the nitrogen-containing film increases in the direction towards the substrate.

21. The method of claim 19, wherein the forming further comprises:

c) prior to step b), exposing the substrate to an oxygen-containing gas prior to, during, or after step a).

22. The method of claim 17, wherein the nitrogen:

oxygen ratio in the nitrided high-k film monotonically varies through the thickness thereof.

23. The method of claim 17, wherein the nitrogen-containing film, the oxygen-containing film, or both, further comprise aluminum, silicon, or aluminum and silicon.

24. The method of claim 17, further comprising:

exposing the nitrided high-k film to an oxygen-containing gas to further incorporate oxygen into the nitrided high-k film.