Method for the deposition and modification of thin films using a combination of vacuum arcs and plasma immersion ion implantation

• US 5,580,429 A
• Filed: 06/07/1995
• Issued: 12/03/1996
• Est. Priority Date: 08/25/1992
• Status: Expired due to Fees

• Current Assignee: Northeastern University
• Original Assignee: Northeastern University
• Inventors: Allen, Ryne C., Husein, Imad, Zhou, Yaunzhong, Chan, Chung
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US08/475,002
• Time in Patent Office: 545 Days
• Field of Search: 204/192.38, 204/298.41, 427/580
• US Class Current: 204/192.38
• CPC Class Codes: C23C 14/325 Electric arc evaporation
• CPC Class Codes: H01J 37/32055 Arc discharge

Abstract

Cathodic/anodic vacuum arc sources with plasma ion implantation deposition system for depositing high quality thin film coatings of complex compounds on a workpiece. Both cathodic and anodic vacuum arc deposition sources, CAVAD, are used to create a plasma vapor from solid materials composing the cathode and/or anode in the cathodic and/or anodic arc respectively. Gases, e.g., hydrogen or nitrogen can be in the deposited films by creating a background plasma of the desired gas using either RF energy, thermionic emission, or consequential ionization of the gas passing through the arc or around the substrate. Application of highly negative pulses to the substrate to extract the ions and provide them with the appropriate energy to interact with the other species in the thin film formation on the substrate to form the desired films. The substrate is bombarded with the ionized particles to form carbon nitrides with variable [N]/[C] ratios, referred to as CN_x.

Claims

1. A method for depositing a CN_x film on a substrate, comprising the step of:

providing a vacuum chamber;

providing a substrate positioned within said vacuum chamber;

providing a consumable carbon-based anode and a cathode;

ingiting an arc between said consumable carbon-based anode and said cathode to produce a partially ionized carbon vapor;

depositing said partially ionized carbon vapor on said substrate to form a carbon film thereon;

providing a nitrogen plasma;

immersing said substrate deposited with said carbon film into said nitrogen plasma; and

implanting said carbon film with nitrogen ions from said nitrogen plasma to form a CN_x film.

2. The method of claim 1, wherein in said implanting step, said substrate is pulsed with a negative voltage.

3. The method of claim 2, wherein said negative voltage is in the range of approximately -50 to -2000 volts.

4. The method of claim 2, wherein the pulse time is in the range of approximately 3 to 10 μ

sec.

5. The method of claim 1, wherein in said implanting step, said nitrogen plasma is maintained at a pressure of approximately 10^-4 Torr.

6. The method of claim 1, wherein said substrate is made of silicon.

7. The method of claim 6, wherein said substrate is a silicon wafer.

8. The method of claim 1, wherein said substrate is a magnetic computer disk.

9. The method of claim 1, wherein said CN_x film is formed to a thickness in the range of approximately 0.8 to 1.7 μ

m.

10. The method of claim 1, wherein the formation rate of said CN_x film is approximately 0.5 μ

m per min.

11. The method of claim 1, wherein said partially ionized carbon vapor is approximately 20% ionized.

12. The method of claim 1, wherein said nitrogen plasma is produced by thermionic emission.

13. The method of claim 1, wherein said nitrogen plasma is produced by RF excitation.

14. The method of claim 1, wherein said nitrogen plasma is produced by the energy of said cathode.

15. A method for depositing a CN_x film on a substrate, comprising the steps of:

providing a vacuum chamber with a curved magnetic duct, said vacuum chamber including nitrogen gas;

providing a substrate positioned within said vacuum chamber;

providing a cathode positioned at an end of said curved magnetic duct, said cathode comprising a carbon-based material;

igniting a cathodic arc, said cathodic arc operating in a continuous mode and forming a carbon ion flux, said nitrogen gas forming a plasma;

passing said carbon ion flux through said curved magnetic duct and onto said substrate;

implanting said carbon ion flux and nitrogen ions from said nitrogen plasma onto said substrate to form a CN_x film thereon.

16. The method of claim 15, wherein said carbon ion flux is a highly ionized carbon ion flux.

17. The method of claim 15, wherein said substrate is made of silicon.

18. The method of claim 17, wherein said substrate is a silicon wafer.

19. The method of claim 15, wherein said nitrogen gas in said vacuum chamber is maintained at a pressure of approximately 10^-4 Torr.

20. The method of claim 15, wherein in said implanting step, said substrate is pulsed with a negative voltage.

21. The method of claim 20, wherein said negative voltage is in the range of approximately -50 to approximately -2000 volts.

22. The method of claim 20, wherein the pulse time is in the range of from approximately 4 μ

sec to approximately 10 μ

sec.

23. The method of claim 20, wherein the frequency of said pulsing is in the range of from approximately 6 to approximately 14 Khz.

24. The method of claim 15, wherein said CN_x film is formed to a thickness of approximately 0.8 μ

m.

25. The method of claim 15, wherein the formation rate of said CN_x film is approximately 0.1 μ

m per min.

26. The method of claim 15, wherein said nitrogen plasma is produced by thermionic emission.

27. The method of claim 15, wherein said nitrogen plasma is produced by RF excitation.

28. The method of claim 15, wherein said nitrogen plasma is produced by the energy of said cathodic arc.

29. A method for depositing a CN_x film on a substrate, comprising the steps of:

providing a vacuum chamber with a curved magnetic duct, said vacuum chamber including nitrogen gas;

providing a substrate positioned within said vacuum chamber;

providing a cathode positioned at an end of said curved magnetic duct, said cathode comprising a carbon-based material;

igniting a cathodic arc, said cathodic arc operating in a pulsing mode and forming a carbon ion flux;

providing a nitrogen plasma;

passing said carbon ion flux through said curved magnetic duct and onto said substrate;

implanting said carbon ion flux and nitrogen ions from said nitrogen plasma onto said substrate to form a CN_x film.

30. The method of claim 29, wherein said carbon ion flux is a highly ionized carbon ion flux.

31. The method of claim 29, wherein said substrate is made of silicon.

32. The method of claim 29, wherein said nitrogen gas in said vacuum chamber is maintained at a pressure of approximately 10^-4 Torr.

33. The method of claim 29, wherein in said implanting step, said substrate is pulsed with a negative voltage.

34. The method of claim 33, wherein said negative voltage is in the range of approximately -50 to approximately -2000 volts.

35. The method of claim 33, wherein the pulse time is in the range of from approximately 4 μ

sec to approximately 8 μ

sec.

36. The method of claim 33, wherein the frequency of said pulsing is in the range of approximately 6 Khz to approximately 14 Khz.

37. The method of claim 29, wherein said CN_x film is formed to a thickness of approximately 1.0 μ

m.

38. The method of claim 29, wherein the pulse rate of said cathode operating in said pulsing mode are in the range of approximately 1 to 10 per second.

39. The method of claim 29, wherein the duration of the pulses of said cathode operating in said pulsing mode are approximately 1.5 msec.

40. The method of claim 29, wherein said nitrogen plasma is produced by thermionic emission.

41. The method of claim 29, wherein said nitrogen plasma is produced by RF excitation.

42. The method of claim 29, wherein said nitrogen plasma is produced by the energy of the cathodic arc.