METHOD OF GROWING ELECTRICAL CONDUCTORS

• US 20080146042A1
• Filed: 02/28/2008
• Published: 06/19/2008
• Est. Priority Date: 05/15/2000
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Soininen, Pekka J., Elers, Kai-Erik, Haukka, Suvi, Kostamo, Juhana
• Granted Patent: US 7,955,979 B2
• Time in Patent Office: Days
• US Class Current: 438/778
• CPC Class Codes: C23C 16/40 Oxides
• CPC Class Codes: C23C 16/406 of iron group metals
• CPC Class Codes: C23C 16/408 of copper or solid solutions thereof
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76861 Post-treatment or after-treatment not introducing additional chemical elements into the layer
• CPC Class Codes: H01L 21/76862 Bombardment with particles, e.g. treatment in noble gas plasmas; UV irradiation
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 21/76874 for electroless plating
• CPC Class Codes: H01L 21/76886 Modifying permanently or temporarily the pattern or the conductivity of conductive members, e.g. formation of alloys, reduction of contact resistances

Abstract

A method for forming a conductive thin film includes depositing a metal oxide thin film on a substrate by an atomic layer deposition (ALD) process. The method further includes at least partially reducing the metal oxide thin film by exposing the metal oxide thin film to a reducing agent, thereby forming a seed layer. In one arrangement, the reducing agent comprises one or more organic compounds that contain at least one functional group selected from the group consisting of —OH, —CHO, and —COOH. In another arrangement, the reducing agent comprises an electric current.

Claims

1. A method of depositing a noble metal oxide on a substrate in a reaction chamber by a plurality of atomic layer deposition (ALD) cycles, each cycle comprising:

contacting the substrate with a vapor-phase pulse of a first noble metal source chemical, wherein the first source chemical adsorbs no more than one monolayer of a noble metal species on the substrate;

purging the reaction chamber of excess first source chemical;

contacting the substrate with a vapor-phase pulse of a second oxygen source chemical, wherein the second source chemical oxidizes the noble metal species on the substrate into a noble metal oxide; and

purging the reaction chamber of excess second source chemical.

2. The method of claim 1, wherein the second source chemical is selected from at least one of the group consisting of water (H₂O), hydrogen peroxide (H₂O₂), ozone (O₃), oxygen (O₂), singlet oxygen ¹O₂, oxygen compounds with unpaired electrons, and oxygen and OH radicals.

3. The method of claim 1, further comprising contacting the substrate with a vapor-phase pulse of a third oxygen source chemical.

4. The method of claim 3, wherein the substrate is simultaneously contacted with water vapor (H₂O) and ozone (O₃).

5. The method of claim 1, wherein the noble metal species is selected from the group consisting of Re, Ru, Os, Rh, Ir, Ni, Pd, Pt, Ag, and Au.

6. The method of claim 1, wherein the metal oxide is selected from the group consisting of ReO₂, Re₂O₅, ReO₃, RuO₂, OsO₂, Rh₂O₃, RhO₂, IrO₂, PdO, PtO₂, AgO, Ag₂O, Au₂O₃.

7. The method of claim 1, wherein the first source chemical comprises an anhydrous metal nitrate.

8. The method of claim 7, wherein the second source chemical is selected from NH₃*H₂O, NH₄OH, NH₂OH*H₂O, and N₂H₄*H₂O.

9. The method of claim 1, wherein the metal oxide thin film is at least 0.6 nanometers thick.

10. The method of claim 1, wherein the metal oxide thin film has a thickness between approximately 0.1 nanometer and approximately 10 nanometers.

11. The method of claim 1, wherein the metal oxide thin film has a thickness between approximately 1 nanometer and approximately 20 nanometers.

12. The method of claim 1, wherein the metal oxide thin film has a thickness between approximately 1 nanometer and approximately 3 nanometers.

13. The method of claim 1, wherein the metal oxide thin film has a resistivity of less than about 500 μ

Ω

-cm.

14. The method of claim 1, wherein the metal oxide thin film has a resistivity of less than about 300 μ

Ω

-cm.

15. The method of claim 1, wherein the metal oxide thin film has a resistivity of less than about 100 μ

Ω

-cm.

16. The method of claim 1, wherein depositing comprises at least three ALD cycles.

17. The method of claim 1, wherein the metal oxide is used as an electrode.

18. The method of claim 17, wherein the electrode is part of a capacitor.

19. The method of claim 17, wherein the electrode is the gate electrode of a transistor.

20. The method of claim 1, wherein the metal oxide is deposited on a high-k layer.

21. A method of depositing ruthenium oxide on a substrate in a reaction chamber by an atomic layer deposition process comprising:

providing a pulse of a ruthenium halide into the reaction chamber;

purging the reaction chamber of excess ruthenium halide;

providing a pulse of a reducing agent into the reaction chamber;

purging the reaction chamber of excess reducing agent;

providing a pulse of an oxygen source into the reaction chamber; and

purging the reaction chamber of excess oxygen source.

22. The method of claim 21, wherein the ruthenium oxide is selected from RuO₂ and RuO₄.

23. The method of claim 22, wherein the ruthenium oxide comprises a ternary ruthenium compound.

24. The method of claim 22, wherein the ruthenium oxide has a resistivity of about 35 μ

Ω

-cm.

25. The method of claim 21, wherein the ruthenium halide is chosen from a group consisting of RuF₅ and RuF₆.

26. The method of claim 21, wherein the reducing agent comprises at least one of alcohols, aldehydes, carboxylic acids, and hydrogen radicals.

27. The method of claim 21, wherein the oxygen source is chosen from a group consisting of water (H₂O), hydrogen peroxide (H₂O₂), ozone (O₃), oxygen (O₂), singlet oxygen ¹O₂, oxygen compounds with unpaired electrons, and oxygen and OH radicals.

28. A method of depositing SrRuO₃ by ALD comprising:

contacting a substrate with alternate vapor phase pulses of a Sr compound, a Ru compound and an oxygen compound.

29. The method of claim 28, wherein the oxygen compound is chosen from a group consisting of water (H₂O), hydrogen peroxide (H₂O₂), ozone (O₃), oxygen (O₂), singlet oxygen ¹O₂, oxygen compounds with unpaired electrons, and oxygen and OH radicals.