Selective silicide process

• US 8,293,597 B2
• Filed: 04/11/2011
• Issued: 10/23/2012
• Est. Priority Date: 12/19/2008
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Raaijmakers, Ivo
• Primary Examiner(s): Pham, Hoai V
• Application Number:
  US13/084,341
• Publication Number:
  US 20110269310A1
• Time in Patent Office: 561 Days
• Field of Search: 438/197, 438/199, 438/583, 438/682, 438/754, 438/755, 438/E21.632
• US Class Current: 438/199
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/28518 the conductive layers comprising silicides H01L21/28537 takes precedence
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76823 transforming an insulating layer into a conductive layer
• CPC Class Codes: H01L 29/665 using self aligned silicidation, i.e. salicide formation of conductive layers comprising silicides H01L21/28518
• CPC Class Codes: H01L 29/66568 Lateral single gate silicon transistors

Abstract

A method of self-aligned silicidation on structures having high aspect ratios involves depositing a metal oxide film using atomic layer deposition (ALD) and converting the metal oxide film to metal film in order to obtain uniform step coverage. The substrate is then annealed such that the metal in regions directly overlying the patterned and exposed silicon reacts with the silicon to form uniform metal silicide at the desired locations.

Claims

1. A method for selective silicidation comprising:

providing a substrate having a non-planar transistor structure, the non-planar transistor structure including silicon regions;

conformally depositing a metal oxide film over the non-planar transistor structure; and

reacting a metal from the metal oxide film with silicon from the silicon regions to form a metal silicide film over at least a portion of the silicon regions.

2. The method of claim 1, wherein the metal oxide comprises two different metals.

3. The method of claim 1, further comprising converting the metal silicide film to a phase of lower resistivity by annealing.

4. The method of claim 1, wherein the metal is chosen from the group consisting of Ru, Rh, Pt and Pd.

5. The method of claim 1, wherein the metal is Ni.

6. The method of claim 1, wherein the non-planar transistor structure comprises a FinFET.

7. The method of claim 1, wherein the non-planar transistor structure comprises a dual-gate transistor.

8. The method of claim 1, wherein the non-planar transistor structure comprises a tri-gate transistor.

9. The method of claim 1, wherein the metal oxide film is conformally deposited using an atomic layer deposition process.

10. The method of claim 1, wherein reacting comprises reducing the metal oxide film to metal and annealing the substrate to form the metal silicide film.

11. The method of claim 10, wherein reducing comprises exposing the metal oxide film to a hydrogen-containing plasma, hydrogen radicals, or hydrogen atoms.

12. The method of claim 10, wherein reducing and annealing are conducted simultaneously.

13. The method of claim 10, wherein reducing and annealing are conducted sequentially.

14. The method of claim 10, wherein annealing is conducted at a temperature from about 200°

C. to about 500°

C.

15. The method of claim 14, wherein annealing has a duration less than about 2 minutes.

16. The method of claim 1, wherein the thickness of the metal silicide film is between about 3 nm and about 200 nm.

17. The method of claim 1, wherein conformally depositing comprises directly forming the metal oxide film on exposed surfaces of the silicon regions.

18. A method for selective silicidation comprising:

providing a substrate comprising a three-dimensional transistor;

forming a metal oxide film over the three-dimensional transistor, the metal oxide film being substantially conformal over the three-dimensional transistor, the metal oxide film formed by alternately and sequentially contacting the substrate with a metal source precursor and an oxygen source precursor;

chemically reducing the metal oxide film; and

annealing the substrate to form a metal silicide film over at least a portion of the substrate, the metal silicide film comprising a metal from the metal oxide film.

19. The method of claim 18, wherein the metal source precursor comprises Ni(cp)₂.

20. The method of claim 18, wherein the oxygen source precursor is chosen from a group consisting of O₂, H₂O, O₃, oxygen plasma, oxygen radicals, oxygen atoms and a reactive oxygen gas.

21. The method of claim 18, wherein chemically reducing the metal oxide film comprises contacting the substrate with a vapor phase reducing agent.

22. The method of claim 21, wherein the vapor phase reducing agent comprises hydrogen.

23. The method of claim 21, wherein the vapor phase reducing agent comprises a hydrogen-containing plasma, hydrogen radicals, or hydrogen atoms.

24. The method of claim 18, wherein chemically reducing and annealing are performed in-situ without exposure to an ambient atmosphere.

25. The method of claim 24, wherein chemically reducing and annealing are conducted at the same temperature.

26. The method of claim 18, wherein chemically reducing and annealing are conducted simultaneously.