Dielectric cure for reducing oxygen vacancies

• US 6,281,142 B1
• Filed: 06/04/1999
• Issued: 08/28/2001
• Est. Priority Date: 06/04/1999
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Sandhu, Gurtej S., Basceri, Cem
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): Lee, Granvill D
• Application Number:
  US09/326,429
• Time in Patent Office: 816 Days
• Field of Search: 438/771, 438/240, 438/222, 438/262, 438/404, 438/402, 257/103, 257/236, 257/243, 257/310, 322/10
• US Class Current: 438/771
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 28/55 with a dielectric comprising a perovskite structure material
• CPC Class Codes: H01L 28/84 being a rough surface, e.g. using hemispherical grains

Abstract

A unique electrochemical process fills oxygen vacancies in dielectrics while reducing oxidation of nearby electrodes and conductors. Preferably, an electromagnetic field or bias is applied to a dielectric. The bias causes oxygen vacancies in the dielectric to migrate to the surface of the dielectric. As the oxygen vacancies migrate toward the surface, oxygen ions fill the oxygen vacancies. In one embodiment, a unique plasma treatment provides the oxygen ions that react with the oxygen vacancies. In another embodiment, a unique electrolysis treatment provides the oxygen ions that react with the oxygen vacancies.

Claims

1. A method of reducing oxygen vacancies in a high dielectric constant capacitor comprising:

depositing a first electrode on a semiconductor substrate;

depositing a high constant dielectric above the first electrode, the high constant dielectric having a plurality of oxygen vacancies therein;

applying an electrical bias to the high constant dielectric wherein the polarity of the electrical bias causes the oxygen vacancies to migrate towards the surface of the high constant dielectric; and

plasma treating the high constant dielectric with a plurality of oxygen ions at a temperature below 500°

C. wherein the oxygen ions react to fill at least a portion of the oxygen vacancies from the high constant dielectric.

2. The method of claim 1 wherein the electrical bias causes the oxygen vacancies to migrate to an exposed surface of the dielectric.

3. The method of claim 1 wherein the act of applying the electric bias applies a voltage to the dielectric.

4. The method of claim 1 wherein the act of plasma treating occurs between a temperature range of approximately 300°

C. to approximately 500°

C.

5. The method of claim 1 wherein the act of plasma treating occurs at a temperature range of approximately 20°

C. to approximately 500°

C.

6. A method of reducing oxygen vacancies in a dielectric comprising:

applying an electromagnetic field to a dielectric to cause oxygen vacancies in the dielectric to migrate towards the surface of the dielectric; and

plasma treating the dielectric with oxygen ions which react with at least a portion of the oxygen vacancies in the dielectric.

7. The method of claim 6 wherein the act of applying an electromagnetic field applies an electrical current to the dielectric.

8. The method of claim 6 wherein the act of applying an electromagnetic field applies an electrical voltage to the dielectric.

9. The method of claim 6 wherein the act of applying an electromagnetic filed applies a magnetic field to the dielectric.

10. The method of claim 6 wherein the act of applying an electromagnetic field applies a substantially uniform field across the dielectric.

11. A method of reducing oxygen vacancies in a memory cell comprising:

depositing a first electrode over a portion of a poly plug;

depositing a dielectric over the first electrode, the dielectric having a plurality of oxygen vacancies therein;

applying an electromagnetic field that causes the oxygen vacancies in the dielectric to migrate;

plasma treating the dielectric with a plurality of oxygen ions wherein at least a portion of oxygen ions react with the oxygen vacancies in the dielectric; and

depositing a second electrode over at least a portion of the dielectric.

12. The method of claim 11 wherein the act of plasma treating does not substantially degrade the poly plug.

13. The method of claim 11 wherein the act of plasma treating does not substantially oxidize the poly plug.

14. The method of claim 11 wherein the act of depositing the dielectric deposits a layer of BST over the first electrode.

15. The method of claim 11 wherein the act of depositing the dielectric deposits a layer of tantalum pentoxide over the first electrode.

16. The method of claim 11 further comprising the act of depositing a barrier layer between the poly plug and the dielectric.

17. The method of claim 11 wherein the act of depositing the first electrode deposits platinum.

18. The method of claim 17 further comprising the act of depositing a titanium nitride barrier layer over at least a portion of the platinum.

19. The method of claim 18 wherein the act of plasma treating the high constant dielectric does not oxidize the poly plug.

20. A method of reducing oxygen vacancies in a metal-insulator-metal structure comprising:

depositing a first metal electrode over a substrate;

depositing a dielectric over the first metal electrode, the dielectric having a plurality of oxygen vacancies therein;

applying an electromagnetic field that causes the oxygen vacancies in the dielectric to migrate;

plasma treating the dielectric with a plurality of oxygen ions wherein the oxygen ions fill at least a portion of the oxygen vacancies in the dielectric; and

depositing a second metal electrode over the dielectric.

21. The method of claim 20 wherein the act of plasma treating the dielectric does not degrade the first metal electrode.

22. The method of claim 20 wherein the act of depositing the first metal electrode deposits the first metal electrode over at least a portion of a poly plug.

23. The method of claim 22 wherein the act of plasma treating the dielectric does not substantially oxidize the poly plug.

24. The method of claim 22 further comprising the act of depositing a barrier layer between the first metal electrode and the poly plug.

25. The method of claim 24 wherein the act of plasma treating the dielectric does not substantially oxidize the barrier layer.

26. The method of claim 20 wherein the act of plasma treating occurs below 500°

C.

27. The method of claim 20 wherein the act of applying an electromagnetic field applies is an electrical current to the dielectric.

28. The method of claim 20 wherein the act of applying an electromagnetic field applies an electrical voltage to the dielectric.

29. A method of reducing oxygen vacancies in a dielectric on a semiconductor, the method comprising:

depositing on a semiconductor substrate, a high constant dielectric, the high constant dielectric having a plurality of oxygen vacancies therein;

applying an electromagnetic field to the dielectric wherein the electromagnetic field causes the oxygen vacancies in the high constant dielectric to migrate towards the surface of the high constant dielectric; and

applying an electrolytic solution to the high constant dielectric wherein the electrolytic solution comprises at least a portion of oxygen ions that react with the oxygen vacancies to thereby fill a portion of the oxygen vacancies from the high constant dielectric.

30. The method of claim 29 wherein the electromagnetic field causes the oxygen vacancies to migrate to an exposed surface of the dielectric.

31. The method of claim 29 wherein the act of applying the electromagnetic field applies a voltage to the dielectric.

32. The method of claim 29 wherein the act of applying an electrolytic solution occurs between approximately 300°

C. to approximately 500°

C.

33. The method of claim 29 wherein the act of applying the electrolytic solution occurs between approximately 20°

C. to approximately 100°

C.

34. A method of reducing oxygen vacancies in a dielectric comprising:

applying an electromagnetic field to a dielectric to cause oxygen vacancies in the dielectric to migrate towards the surface of the dielectric; and

applying an electrolytic solution to the dielectric wherein oxygen ions in the electrolytic solution react with at least a portion of the oxygen vacancies in the dielectric.

35. The method of claim 34 wherein the act of applying an electromagnetic field applies an electrical current to the dielectric.

36. The method of claim 34 wherein the act of applying an electromagnetic field applies an electrical voltage to the dielectric.

37. The method of claim 34 wherein the act of applying an electromagnetic filed applies a magnetic field to the dielectric.

38. The method of claim 34 wherein the act of applying an electromagnetic field applies a substantially uniform field across the dielectric.

39. The method of claim 34 wherein the act of applying an electrolytic solution occurs between approximately 20°

C. and 100°

C.

40. The method of claim 34 wherein the act of applying an electrolytic solution occurs between approximately 20°

C. and approximately 100°

C.

41. A method of reducing oxygen vacancies in a memory cell comprising:

depositing a first electrode over a portion of a semiconductor transistor structure;

depositing a dielectric over the first electrode, the dielectric having a plurality of oxygen vacancies therein;

applying an electromagnetic field that causes the oxygen vacancies in the dielectric to migrate;

subjecting the dielectric to electrolysis wherein oxygen ions react with the oxygen vacancies in the dielectric; and

depositing a second electrode over the dielectric.

42. The method of claim 41 wherein the act of applying an electromagnetic field applies current bias in the range of voltage of approximately 250 to 2,000 kilovolts per centimeter.

43. The method of claim 41 wherein the semiconductor transistor structure comprises a poly plug.

44. The method of claim 41 further comprising the act of depositing a barrier layer between the first electrode and the poly plug.

45. The method of claim 41 wherein the act of subjecting the dielectric to electrolysis does not oxidize a poly plug in the transistor structure.

46. A method of reducing oxygen vacancies in a metal-insulator-metal structure comprising:

depositing a first metal electrode over a substrate;

depositing a dielectric over the first metal electrode, the dielectric having a plurality of oxygen vacancies therein;

applying an electromagnetic field that causes the oxygen vacancies in the dielectric to migrate;

subjecting the dielectric to electrolysis wherein oxygen ions react with at least a portion of the oxygen vacancies in the dielectric; and

depositing a second metal electrode over the dielectric.

47. The method of claim 46 wherein the act of subjecting the dielectric to electrolysis does not substantially oxidize the first metal electrode.

48. The method of claim 46 wherein the act of depositing the first metal electrode deposits the first metal electrode over at least a portion of a poly plug.

49. The method of claim 48 wherein the act of subjecting the dielectric to electrolysis does not substantially oxidize the poly plug.

50. The method of claim 48 further comprising the act of depositing a barrier layer between the first metal electrode and the poly plug.

51. The method of claim 50 wherein the act of subjecting the dielectric to electrolysis does not substantially oxidize the barrier layer.

52. The method of claim 46 wherein the subjecting the dielectric to electrolysis does not substantially oxidize the substrate.

53. A method of reducing oxygen vacancies in a dielectric comprising:

applying an electromagnetic field to a dielectric having oxygen vacancies therein; and

applying an electrolytic solution to the dielectric wherein oxygen ions in the electrolytic solution react with at least a portion of the oxygen vacancies in the dielectric.

54. A method of reducing oxygen vacancies in a dielectric comprising:

applying an electromagnetic field to a dielectric to cause oxygen vacancies in the dielectric to migrate; and

applying oxygen ions to the surface of the dielectric wherein the oxygen ions react with the migrating oxygen vacancies.

55. A method of reducing oxygen vacancies comprising:

applying an electromagnetic field that causes the oxygen vacancies in a material to migrate; and

reducing the amount of oxygen vacancies by subjecting the material to an oxidizing treatment.

56. The method of claim 55 wherein the material is a dielectric.

57. The method of claim 55 wherein the electromagnetic field causes the oxygen vacancies to migrate to the surface of the material.

58. The method of claim 55 wherein the electromagnetic field is an electrical bias.

59. The method of claim 55 wherein subjecting the material to an oxidizing treatment comprises plasma treating the material.

60. The method of claim 59 wherein the plasma treating applies oxygen ions to the material.

61. The method of claim 55 wherein subjecting the material to an oxidizing treatment applies an electrolytic solution to the material.

62. The method of claim 61 wherein the electrolytic solution applies a plurality of oxygen ions to the material.