Method of forming mixed rare earth nitride and aluminum nitride films by atomic layer deposition

• US 8,012,442 B2
• Filed: 03/31/2006
• Issued: 09/06/2011
• Est. Priority Date: 03/31/2006
• Status: Expired due to Fees

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Clark, Robert D.
• Primary Examiner(s): Johnson; Edward
• Application Number:
  US11/278,393
• Publication Number:
  US 20070237698A1
• Time in Patent Office: 1,985 Days
• Field of Search: 427/248.1, 427/250, 427/253.19, 427/263, 427/255.19, 423/263
• US Class Current: 423/263
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02192 the material containing at least one rare earth metal element, e.g. oxides of lanthanides, scandium or yttrium
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/3142 of nano-laminates, e.g. alternating layers of Al203-Hf02
• CPC Class Codes: H01L 21/318 composed of nitrides

Abstract

A method is provided for depositing a gate dielectric that includes at least two rare earth metal elements in the form of a nitride or an aluminum nitride. The method includes disposing a substrate in a process chamber and exposing the substrate to a gas pulse containing a first rare earth precursor and to a gas pulse containing a second rare earth precursor. The substrate may also optionally be exposed to a gas pulse containing an aluminum precursor. Sequentially after each precursor gas pulse, the substrate is exposed to a gas pulse of a nitrogen-containing gas. In alternative embodiments, the first and second rare earth precursors may be pulsed together, and either or both may be pulsed together with the aluminum precursor. The first and second rare earth precursors comprise a different rare earth metal element. The sequential exposing steps may be repeated to deposit a mixed rare earth nitride or aluminum nitride layer with a desired thickness. Purge or evacuation steps may also be performed after each gas pulse.

Claims

1. A method for forming a mixed rare earth nitride or a mixed rare earth aluminum nitride film, comprising:

disposing a substrate in a process chamber; and

exposing the substrate to a gas pulse sequence to deposit a mixed rare earth nitride film or a mixed rare earth aluminum nitride film with a desired thickness, wherein the gas pulse sequence includes, in any order;

a) sequentially first, exposing the substrate to a gas pulse comprising a first rare earth precursor, and second, exposing the substrate to a gas pulse comprising a nitrogen-containing gas;

b) sequentially first, exposing the substrate to a gas pulse comprising a second rare earth precursor, and second, exposing the substrate to a gas pulse comprising the nitrogen-containing gas, wherein the first and second rare earth precursors contain different rare earth metal elements of differing and mismatched atomic sizes; and

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

wherein each of a), b) and optionally c) are optionally repeated any number of desired times, wherein the gas pulse sequence including a), b) and optionally c) is optionally repeated, in any order, any number of desired times to achieve the desired thickness, and wherein the different rare earth metal elements are in solid solution in the mixed rare earth nitride or the mixed rare earth aluminum nitride film and wherein the mixed rare earth nitride or the mixed rare earth aluminum nitride film has a dielectric constant that is greater than the dielectric constant of a nitride or an aluminum nitride film having only one of the different rare earth metal elements present in the mixed rare earth nitride or the mixed rare earth aluminum nitride film.

2. The method of claim 1, wherein the rare earth metal elements in the first and second rare earth precursors are selected from Y, Lu, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb.

3. The method of claim 1, wherein the nitrogen-containing gas comprises NH₃, N₂H₄, or plasma excited nitrogen, or a combination thereof.

4. The method of claim 1, wherein a) comprises:

alternating the first and second exposing steps a plurality of times.

5. The method of claim 1, wherein b) comprises:

alternating the first and second exposing steps a plurality of times.

6. The method of claim 1, wherein c) comprises:

alternating the first and second exposing steps a plurality of times.

7. The method of claim 1, further comprising purging or evacuating the process chamber after at least one of a), b) or c).

8. The method of claim 1, further comprising purging or evacuating the process chamber between the first and second exposing steps in at least one of a), b) or c).

9. The method of claim 1, further comprising:

performing one or more additional exposure steps, wherein each additional exposure step comprises sequentially first, exposing the substrate to a gas pulse comprising an additional rare earth precursor, and second, exposing the substrate to a gas pulse comprising the nitrogen-containing gas, wherein each additional rare earth precursor contains a different rare earth metal element than the rare earth metal elements in the first and second rare earth precursors.

10. The method of claim 1, wherein the mixed rare earth nitride or the mixed rare earth aluminum nitride film has a thickness between about 5 and about 200 angstroms.

11. The method of claim 1, wherein the first exposing steps in a) and b) are performed concurrently and the second exposing steps in a) and b) are performed concurrently, whereby to sequentially first expose the substrate to a gas pulse comprising both the first and second rare earth precursors, and second expose the substrate to a gas pulse comprising the nitrogen-containing gas.

12. A method for forming a mixed rare earth nitride film, comprising:

a) disposing a substrate in a process chamber;

b) exposing the substrate to a gas pulse comprising a plurality of rare earth precursors containing at least two different rare earth metal elements;

c) exposing the substrate to a gas pulse of an nitrogen-containing gas; and

d) repeating steps b) and c) a desired number of times to deposit a mixed rare earth nitride film with a desired thickness, wherein the at least two different rare earth metal elements are of differing and mismatched atomic size and are in solid solution in the mixed rare earth nitride film and wherein the mixed rare earth nitride film has a dielectric constant that is greater than the dielectric constant of a nitride film having only one of the different rare earth metal elements present in the mixed rare earth nitride film.

13. The method of claim 12, wherein the at least two rare earth metal elements are selected from Y, Lu, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb.

14. The method of claim 12, wherein the nitrogen-containing gas comprises NH₃, N₂H₄, or plasma excited nitrogen, or a combination thereof.

15. The method of claim 12, further comprising purging or evacuating the process chamber after at least one of the exposing steps.

16. The method of claim 12, wherein the mixed rare earth nitride film has a thickness between about 5 and about 200 angstrom.

17. A method for forming a mixed rare earth aluminum nitride film, comprising:

a) disposing a substrate in a process chamber;

b) sequentially first, exposing the substrate to a gas pulse comprising a plurality of rare earth precursors containing at least two different rare earth metal elements, and second, exposing the substrate to a gas pulse of an nitrogen-containing gas;

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

d) repeating steps b)-c) a desired number of times to deposit a mixed rare earth aluminum nitride film with a desired thickness, wherein the at least two different rare earth metal elements are of differing and mismatched atomic size and are in solid solution in the mixed rare earth aluminum nitride film and wherein the mixed rare earth aluminum nitride film has a dielectric constant that is greater than the dielectric constant of an aluminum nitride film having only one of the different rare earth metal elements present in the mixed aluminum nitride film.

18. The method of claim 17, wherein the at least two rare earth metal elements are selected from Y, Lu, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb.

19. The method of claim 17, wherein the nitrogen-containing gas comprises NH₃, N₂H₄, or plasma excited nitrogen, or a combination thereof.

20. The method of claim 17, further comprising purging or evacuating the process chamber after at least one of b) or c).

21. The method of claim 17, further comprising purging or evacuating the process chamber between the first and second exposing steps in at least one of b) or c).

22. A method for forming a mixed rare earth aluminum nitride film, comprising:

a) disposing a substrate in a process chamber;

b) exposing the substrate to a gas pulse comprising a plurality of rare earth precursors containing at least two different rare earth metal elements and containing an aluminum precursor;

c) exposing the substrate to a gas pulse of a nitrogen-containing gas;

d) repeating steps b)-c) a desired number of times to deposit a mixed rare earth aluminum nitride film with a desired thickness, wherein the at least two different rare earth metal elements are of differing and mismatched atomic size and are in solid solution in the mixed rare earth aluminum nitride film and wherein the mixed rare earth aluminum nitride film has a dielectric constant that is greater than the dielectric constant of an aluminum nitride film having only one of the different rare earth metal elements present in the mixed rare earth aluminum nitride film.

23. The method of claim 22, wherein the rare earth metal elements are selected from Y, Lu, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb.

24. The method of claim 22, wherein the nitrogen-containing gas comprises NH₃, N₂H₄, or plasma excited nitrogen, or a combination thereof.

25. The method of claim 22, further comprising purging or evacuating the process chamber after at least one of the exposing steps.