PROCESS FOR PASSIVATING DIELECTRIC FILMS

• US 20120269962A1
• Filed: 10/14/2010
• Published: 10/25/2012
• Est. Priority Date: 10/20/2009
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Blomberg, Tom E., Maes, Jan Willem, Machkaoutsan, Vladimir, Pierreux, Dieter, Tois, Eva E., Huggare, Robert
• Granted Patent: US 10,513,772 B2
• Time in Patent Office: Days
• US Class Current: 427/126.3
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/36 Carbonitrides
• CPC Class Codes: C23C 16/409 of the type ABO3 with A representing alkali, alkaline earth metal or lead and B representing a refractory metal, nickel, scandium or a lanthanide
• CPC Class Codes: C23C 16/45527 characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions

Abstract

Methods are disclosed herein for depositing a passivation layer comprising fluorine over a dielectric material that is sensitive to chlorine, bromine, and iodine. The passivation layer can protect the sensitive dielectric layer thereby enabling deposition using precursors comprising chlorine, bromine, and iodine over the passivation layer.

Claims

1. A process for passivating a high-k layer on a substrate in a reaction chamber comprising:

providing a substrate with a high-k layer in a reaction chamber, wherein the high-k layer comprises a material that is sensitive to reaction with compounds comprising chlorine, bromine or iodine; and

providing a fluorine containing chemical into the reaction chamber in a vapor phase, such that the fluorine containing chemical reacts with the high-k layer to form a passivation layer comprising fluorine and a metal from the high-k material.

2. The process of claim 1, wherein the fluorine containing chemical comprises a metal.

3. The process of claim 2, wherein the metal comprises Ti, Ta, Nb, W, Mo, V, Ru, or Ir.

4. The process of claim 3, wherein the fluorine containing chemical is selected from the group consisting of:

TiF₄, TaF₅, NbF₅, WF_x, MoF_x, VF_x, RuF_x, and IrF_x.

5. The process of claim 1, further comprising depositing an electrode on the passivation layer.

6. The process of claim 5, wherein the electrode is formed using ALD or CVD.

7. The process of claim 5, wherein the electrode is formed using a precursor comprising Cl, I, or Br.

8. The process of claim 5, wherein the electrode comprises titanium.

9. The process of claim 8, wherein the electrode is deposited using TiCl₄.

10. The process of claim 1, wherein the high-k layer comprises Sr or Ba.

11. The process of claim 10, wherein the high-k layer comprises SrTi_xO_y, BaTi_xO_y, Sr_xBa_(1-x)Ti_yO_z, or SrBi_xTa_yO_z.

12. The process of claim 1, wherein the fluorine containing chemical comprises NF₃, F₂, C_xH_yF_z, HF, CF₄, SF₆, plasma excited fluorine compounds, or atomic fluorine.

13. The process of claim 1, wherein providing a fluorine containing compound comprises annealing the high-k layer in an atmosphere comprising fluorine.

14. The process of claim 1, further comprising depositing a layer comprising metal oxide on the passivation layer.

15. The process of claim 14, wherein the layer comprising metal oxide is deposited using a precursor comprising bromine, chorine, or iodine.

16. The process of claim 10, wherein the passivation layer comprises Sr and fluorine.

17. The process of claim 5, wherein the electrode comprises TiN and is deposited using a compound comprising fluorine.

18. The process of claim 17, wherein the TiN electrode comprises greater than 2 atomic % fluorine.

19. The process of claim 17, wherein the TiN electrode layer has a thickness of less than about 10 nm and has a resistivity of less than 500 μ

Ω

cm.

20. A process for forming a passivation layer film for a high-k layer on a substrate in a reaction chamber comprising:

providing a substrate with a high-k material, wherein the high-k layer comprises Sr or Ba;

contacting the high-k material with a vapor phase pulse of a fluorine containing chemical to form a passivation layer; and

contacting the substrate with a pulse of a vapor phase reactant comprising nitrogen such that the vapor phase reactant comprising nitrogen reacts with the fluorine containing chemical on the substrate to form a layer comprising nitrogen.

21. The process of claim 20, wherein the contacting steps are repeated less than about 10 times.

22. The process of claim 20, wherein the vapor phase reactant comprising nitrogen comprises NH₃.

23. The process of claim 20, wherein the fluorine containing chemical comprises a metal.

24. The process of claim 23, wherein the metal comprises Ti, Ta, Nb, W, Mo, V, Ru, or Ir.

25. The process of claim 23, wherein the fluorine containing chemical is selected from the group consisting of:

TiF₄, TaF₅, NbF₅, WF_x, MoF_x, VF_x, RuF_x, and IrF_x.

26. The process of claim 20, wherein the high-k layer comprises SrTi_xO_y, BaTi_xO_y, Sr_xBa_(1-x)Ti_yO_x, or SrBi_xTa_yO_z.

27. The process of claim 20, further comprising depositing a material on the passivation layer using a compound comprising chlorine, bromine, or iodine.

28. An atomic layer deposition (ALD) process for forming a titanium nitride containing thin film on a substrate in a reaction chamber comprising a plurality of titanium nitride deposition cycles, each cycle comprising:

providing a pulse of titanium fluoride into the reaction chamber in a vapor phase to form no more than about a single molecular layer of the titanium fluoride on the substrate;

removing excess titanium fluoride from the reaction chamber;

providing a pulse of a nitrogen containing vapor phase reactant to the reaction chamber such that the nitrogen containing vapor phase reactant reacts with the titanium fluoride on the substrate to form a titanium nitride containing thin film; and

removing excess nitrogen containing vapor phase reactant and reaction byproducts, if any, from the reaction chamber.

29. The process of claim 28, wherein the titanium nitride film is formed on top of a dielectric film comprising Sr or Ba.

30. The process of claim 28, wherein less than 10 titanium nitride deposition cycles are performed.

31. The process of claim 28, wherein the titanium nitride thin film is deposited to a thickness of less than about 15 Å

.

32. A chemical vapor deposition (CVD) process for forming a titanium nitride containing thin film on a substrate in a reaction chamber comprising:

providing a substrate with a high-k layer in a reaction chamber, wherein the high-k layer comprises a material that is sensitive to reaction with compounds comprising chlorine;

providing vapor phase titanium fluoride to the reaction chamber;

providing a vapor phase reactant comprising nitrogen to the reaction chamber such that the nitrogen containing vapor phase reactant reacts with the titanium fluoride to form a thin film comprising titanium nitride.

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42. A process for forming a titanium nitride containing thin film on a substrate in a reaction chamber comprising:

providing titanium fluoride into the reaction chamber in a vapor phase;

providing nitrogen containing vapor phase reactant to the reaction chamber such that the nitrogen containing vapor phase reactant reacts with the titanium fluoride to form a titanium nitride containing thin film;

wherein the nitrogen containing vapor phase reactant comprises NH₃ or N-containing plasma and wherein the formed titanium nitride thin film has a work function of above about 4.9 eV.

43. The process of claim 42, wherein the process for forming a titanium nitride containing thin film is an ALD process.

44. The process of claim 42, wherein the process for forming a titanium nitride containing thin film is a CVD or a pulsed CVD process.

45. The process of claim 42, wherein the formed titanium nitride thin film has a work function above about 5.0 eV.

46. The process of claim 42, wherein the formed titanium nitride thin film has a work function above about 5.2 eV.

47. The process of claim 42, wherein the substrate is susceptible to chloride, bromide, or iodide attack.

48. The process of claim 42, wherein the titanium fluoride is provided to a substrate comprising a high-k surface.

49. The process of claim 48, further comprising depositing a TiN layer over the high-k surface using a titanium precursor comprising a chlorine, bromine, or iodine prior to providing a titanium fluoride.

50. The process of claim 48, wherein the high-k surface comprises hafnium or zirconium.