Nitrogen profile engineering in nitrided high dielectric constant films

• US 7,767,262 B2
• Filed: 09/29/2006
• Issued: 08/03/2010
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Clark, Robert D.
• Primary Examiner(s): Ahmed; Shamim
• Assistant Examiner(s): Angadi; Maki A
• Application Number:
  US11/537,245
• Publication Number:
  US 20080081113A1
• Time in Patent Office: 1,404 Days
• Field of Search: 427/248.1, 427/255.28, 438/618, 438/3, 438/622, 438/637, 438/639, 438/627, 438/643, 438/653.7, 438/91, 438/769, 438/792
• US Class Current: 427/248.1
• 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 high-k film on the substrate by;

a) depositing and at least partially oxidizing a nitrogen-containing film by sequentially;

1) exposing the substrate to a first metal-containing precursor, purging or evacuating the process chamber, and exposing the substrate to a nitrogen-containing gas to form a nitrogen-containing film, wherein step (1) is optionally repeated with purging or evacuating the process chamber therebetween; and

(2) exposing the nitrogen-containing film formed in (1) to a first oxygen-containing gas to at least partially oxidize the nitrogen-containing film, and purging or evacuating the process chamber; and

b) depositing an oxygen-containing film by sequentially;

(3) exposing the at least partially oxidized nitrogen-containing film to a second metal-containing precursor, purging or evacuating the process chamber, and exposing the substrate to a second oxygen-containing gas so as to further oxidize at least portion of the thickness of the nitrogen-containing film, wherein step (3) is optionally repeated with purging or evacuating the process chamber therebetween; and

c) optionally repeating steps a) and b), any number of times, with purging or evacuating the process chamber therebetween,

wherein the first and second metal-containing precursors for depositing 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 2, wherein the nitrogen:

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

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

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

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

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

7. 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.

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

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

10. The method of claim 1 wherein step a)(1) comprises:

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

second, purging or evacuating the process chamber; and

third, exposing the substrate to a gas pulse comprising the nitrogen-containing gas;

ii) sequentially first, exposing the substrate to a gas pulse comprising an aluminum or a silicon precursor;

second, purging or evacuating the process chamber; and

third, exposing the substrate to a gas pulse containing the nitrogen-containing gas,

wherein each of i) and ii) are repeated any number of desired times with purging or evacuating the process chamber therebetween.

11. The method of claim 10, 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.

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

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

second, purging or evacuating the process chamber; and

third, exposing the substrate to a gas pulse comprising the oxygen-containing gas;

ii) sequentially first, exposing the substrate to a gas pulse comprising an aluminum or a silicon precursor;

second, purging or evacuating the process chamber; and

third, exposing the substrate to a gas pulse containing the oxygen-containing gas

wherein each of i) and ii) are repeated any number of desired times with purging or evacuating the process chamber therebetween.

13. The method of claim 12, 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.

14. The method of claim 12, wherein the one or more metal elements include hafnium, and wherein step ii) comprises a silicon precursor.

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

disposing a substrate in a process chamber; and

forming a high-k film on the substrate by;

a) depositing an oxygen-containing film by sequentially;

(1) exposing the substrate to a first metal-containing precursor, purging or evacuating the process chamber, exposing the substrate to a first oxygen-containing gas, and purging or evacuating the process chamber,

wherein step a) is optionally repeated any number of times;

b) depositing and at least partially oxidizing a nitrogen-containing film by sequentially;

(2) exposing the substrate to a second metal-containing precursor, purging or evacuating the process chamber, and exposing the substrate to a nitrogen-containing gas to form a nitrogen-containing film, wherein step (2) is optionally repeated any number of times with purging or evacuating the process chamber therebetween;

(3) exposing the nitrogen-containing film to a second oxygen-containing gas to at least partially oxidize the nitrogen-containing film, and purging or evacuating the process chamber;

4) repeating step a); and

c) optionally, repeating steps a) and b),

wherein the first and second metal-containing precursors 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.

16. The method of claim 15, wherein the oxidized portion of the thickness of the nitrogen-containing film comprises a variable nitrogen:

oxygen ratio.

17. The method of claim 16, wherein the nitrogen:

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

18. The method of claim 15, wherein the nitrogen:

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

19. The method of claim 15, wherein the nitrogen-containing film, the oxygen-containing film, or both, further comprise aluminum.

20. The method of claim 15, further comprising:

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

21. The method of claim 15, wherein step a)(1) comprises:

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

second, purging or evacuating the process chamber; and

third, exposing the substrate to a gas pulse comprising the oxygen-containing gas; and

ii) sequentially first, exposing the substrate to a gas pulse comprising an aluminum or a silicon precursor;

second, purging or evacuating the process chamber; and

third, exposing the substrate to a gas pulse containing the oxygen-containing gas;

wherein each of i) and ii) are repeated any number of desired times with purging or evacuating the process chamber therebetween.

22. The method of claim 15, wherein step b) comprises:

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

second, purging or evacuating the process chamber; and

third, exposing the substrate to a gas pulse comprising the nitrogen-containing gas;

ii) sequentially first, exposing the substrate to a gas pulse comprising an aluminum or a silicon precursor;

second, purging or evacuating the process chamber; and

third, exposing the substrate to a gas pulse containing the nitrogen-containing gas;

iii) exposing the nitrogen-containing film to a second oxygen-containing gas to at least partially oxidize the nitrogen-containing film, and purging or evacuating the process chamber; and

iv) repeating step a),

wherein each of i) and ii) are repeated any number of desired times with purging or evacuating the process chamber therebetween.