Diamond Type Quad-Resistor Cells of PRAM

• US 20100258777A1
• Filed: 04/09/2009
• Published: 10/14/2010
• Est. Priority Date: 04/09/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Li, Xia
• Granted Patent: US 8,193,522 B2
• Time in Patent Office: Days
• US Class Current: 257/2
• CPC Class Codes: G11C 13/0004 comprising amorphous/crystalline phase transition cells
• CPC Class Codes: G11C 13/0069 Writing or programming circuits or methods
• CPC Class Codes: G11C 2013/008 Write by generating heat in the surroundings of the memory material, e.g. thermowrite
• CPC Class Codes: G11C 2213/52 Structure characterized by the electrode material, shape, etc.
• CPC Class Codes: H10B 63/80 Arrangements comprising multiple bistable or multi-stable switching components of the same type on a plane parallel to the substrate, e.g. cross-point arrays
• CPC Class Codes: H10B 63/82 the switching components having a common active material layer
• CPC Class Codes: H10N 70/021 Formation of switching materials, e.g. deposition of layers
• CPC Class Codes: H10N 70/063 by etching of pre-deposited switching material layers, e.g. lithography
• CPC Class Codes: H10N 70/231 based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect
• CPC Class Codes: H10N 70/821 Device geometry
• CPC Class Codes: H10N 70/8413 adapted for resistive heating
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe

Abstract

A method of forming a phase-change random access memory (PRAM) cell, and a structure of a phase-change random access memory (PRAM) cell are disclosed. The PRAM cell includes a bottom electrode, a heater resistor coupled to the bottom electrode, a phase change material (PCM) formed over and coupled to the heater resistor, and a top electrode coupled to the phase change material. The phase change material contacts a portion of a vertical surface of the heater resistor and a portion of a horizontal surface of the heater resistor to form an active region between the heater resistor and the phase change material.

Claims

1. A phase-change random access memory (PRAM) cell, comprising:

a heater resistor; and

a phase change material (PCM) formed over and coupled to the heater resistor;

wherein the phase change material (PCM) contacts a portion of a vertical surface of the heater resistor and a portion of a horizontal surface of the heater resistor to form an active region between the heater resistor and the phase change material (PCM).

2. The PRAM cell according to claim 1, wherein the phase change material (PCM) includes a stepped portion.

3. The PRAM cell according to claim 2, further comprising:

a bottom electrode coupled to the heater resistor; and

a top electrode coupled to the phase change material (PCM).

4. The PRAM cell according to claim 3, wherein the top electrode includes a stepped portion.

5. The PRAM cell according to claim 3, wherein the top electrode includes a stepped portion corresponding to the stepped portion of the phase change material (PCM).

6. The PRAM cell according to claim 1, further comprising:

a cap film formed over the heater resistor except for the active region of the heater resistor.

7. The PRAM cell according to claim 6, wherein the phase change material (PCM) includes a stepped portion overlapping the heater resistor and the cap film.

8. The PRAM cell according to claim 7, wherein the stepped portion of the phase change material (PCM) contacts the portion of the vertical surface of the heater resistor, the portion of the horizontal surface of the heater resistor, a portion of a vertical surface of the cap film, and a portion of a horizontal surface of the cap film.

9. The PRAM cell according to claim 6, wherein the active area is a predetermined distance from an edge of the phase change material (PCM) to prevent or reduce etching damage impact on the active region.

10. The PRAM cell according to claim 3, wherein the bottom electrode is coupled to the heater resistor by a first via interconnect.

11. The PRAM cell according to claim 3, further comprising:

a second via interconnect formed over and coupled to the top electrode.

12. The PRAM cell of claim 1 integrated in at least one semiconductor die.

13. The PRAM cell of claim 1, further comprising an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM cell is integrated.

14. A phase-change random access memory (PRAM) arrangement, comprising:

a plurality of phase-change random access memory (PRAM) cells, wherein each of the PRAM cells includes;

a heater resistor; and

a phase change material (PCM) formed over and coupled to the heater resistor;

wherein the phase change material (PCM) contacts a portion of a vertical surface of the heater resistor and a portion of a horizontal surface of the heater resistor to form an active region between the heater resistor and the phase change material (PCM).

15. The PRAM arrangement according to claim 14, wherein the phase change material (PCM) includes a stepped portion.

16. The PRAM arrangement according to claim 15, further comprising:

a bottom electrode coupled to the heater resistor; and

a top electrode coupled to the phase change material (PCM).

17. The PRAM arrangement according to claim 16, wherein the top electrode includes a stepped portion.

18. The PRAM arrangement according to claim 16, wherein the top electrode includes a stepped portion corresponding to the stepped portion of the phase change material (PCM).

19. The PRAM arrangement according to claim 14, further comprising:

a cap film formed over the heater resistor except for the active region of the heater resistor.

20. The PRAM arrangement according to claim 19, wherein the phase change material (PCM) includes a stepped portion overlapping the heater resistor and the cap film.

21. The PRAM arrangement according to claim 20, wherein the stepped portion of the phase change material (PCM) contacts the portion of the vertical surface of the heater resistor, the portion of the horizontal surface of the heater resistor, a portion of a vertical surface of the cap film, and a portion of a horizontal surface of the cap film.

22. The PRAM arrangement according to claim 14, wherein the active area is a predetermined distance from an edge of the phase change material (PCM) to prevent or reduce etching damage impact on the active region.

23. The PRAM arrangement according to claim 14, wherein the phase change material (PCM) is common to each of the plurality of phase-change random access memory (PRAM) cells, and

wherein the common phase change material (PCM) has a central portion and a plurality of portions extending from the central portion to the plurality of PRAM cells.

24. The PRAM arrangement according to claim 23, wherein the central portion of the common phase change material (PCM) has a diamond-shape.

25. The PRAM arrangement according to claim 23, further comprising:

a top electrode coupled to the phase change material (PCM),

wherein the top electrode is common to each of the plurality of phase-change random access memory (PRAM) cells, and

wherein the common top electrode has a central portion and a plurality of portions extending from the central portion to the plurality of PRAM cells.

26. The PRAM arrangement according to claim 25, wherein the central portion of the common top electrode has a diamond-shape.

27. The PRAM arrangement according to claim 14, wherein the heater resistor is common to each of the plurality of phase-change random access memory (PRAM) cells, and

wherein the common heater resistor has a central portion and a plurality of portions extending from the central portion to the plurality of PRAM cells.

28. The PRAM arrangement according to claim 27, further comprising:

a bottom electrode coupled to the heater resistor by a first via interconnect,

wherein the bottom electrode is common to each of the plurality of phase-change random access memory (PRAM) cells.

29. The PRAM arrangement of claim 14 integrated in at least one semiconductor die.

30. The PRAM arrangement of claim 14, further comprising an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM arrangement is integrated.

31. A method of forming a phase-change random access memory (PRAM) cell, the method comprising:

forming a heater resistor; and

forming a phase change material (PCM) over an active region of the heater resistor,

wherein the active region of the heater resistor includes a portion of a vertical surface of the heater resistor and a portion of a horizontal surface of the heater resistor.

32. The method according to claim 31, further comprising:

forming a cap film over the heater resistor except for the active region of the heater resistor,

wherein the phase change material (PCM) is formed over a portion of the cap film.

33. The method according to claim 32, wherein the phase change material (PCM) overlaps the portion of the cap film by a predetermined distance to prevent or reduce etching damage impact on the active region.

34. The method according to claim 31, further comprising:

forming a bottom electrode;

forming a via interconnect on the bottom electrode, wherein the heater resistor is formed over the via interconnect; and

forming a top electrode over the phase change material (PCM).

35. The method according to claim 31, wherein the PRAM cell is applied in an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM cell is integrated.

36. A method of forming a phase-change random access memory (PRAM) cell arrangement, the method comprising:

forming a plurality of heater resistors; and

forming a common phase change material (PCM) film over the plurality of heater resistors.

37. The method according to claim 36, wherein the common phase change material (PCM) film is formed over a portion of a vertical surface of each of the plurality of heater resistors and a portion of a horizontal surface of each of the plurality of heater resistors.

38. The method according to claim 37, further comprising:

forming a cap film over the plurality of heater resistors except for the portion of the horizontal surface of each of the plurality of heater resistors.

39. The method according to claim 38, wherein the common phase change material (PCM) overlaps a portion of the cap film by a predetermined distance to prevent or reduce etching damage impact on an active region between the common phase change material (PCM) and the portion of the vertical surface of each of the plurality of heater resistors and the portion of the horizontal surface of each of the plurality of heater resistors.

40. The method according to claim 36, wherein the common phase change material (PCM) has a central portion and a plurality of portions extending from the central portion to the plurality of heater resistors.

41. The method according to claim 40, wherein the central portion of the common phase change material (PCM) has a diamond-shape.

42. The method according to claim 36, further comprising:

forming a plurality of bottom electrodes;

forming a plurality of via interconnects,

wherein each via interconnect is formed on one of the plurality of bottom electrodes, and

wherein each of the plurality of heater resistors is formed on one of the plurality of via interconnects; and

forming a common top electrode over the common phase change material (PCM).

43. The method according to claim 42, wherein the common top electrode has a central portion and a plurality of portions extending from the central portion to the plurality of heater resistors.

44. The method according to claim 43, wherein the central portion of the common top electrode has a diamond-shape.

45. The method according to claim 36, wherein the PRAM cell is applied in an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM cell is integrated.

47. The method according to claim 36, wherein the common heater resistor has a central portion and a plurality of portions extending from the central portion to the plurality of phase change material (PCM) films.

48. The method according to claim 47, wherein the central portion of the common heater resistor has a diamond-shape.

46. A method of forming a phase-change random access memory (PRAM) cell arrangement, the method comprising:

forming a common heater resistor; and

forming a plurality of phase change material (PCM) films over the common heater resistor.

49. The method according to claim 46, wherein each of the plurality of phase change material (PCM) films contact a portion of a vertical surface of the heater resistor and a portion of a horizontal surface of the heater resistor.

50. The method according to claim 46, further comprising:

forming a common bottom electrode;

forming a common via interconnect on the common bottom electrode; and

forming a plurality of top electrodes over the plurality of phase change material (PCM) films,

wherein the common heater resistor is formed on the via interconnect, and

wherein each of the plurality of top electrodes contact one of the plurality of phase change material (PCM) films.

51. The method according to claim 46, wherein the PRAM cell arrangement is applied in an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM cell arrangement is integrated.

52. A method of forming a three-dimensional phase-change random access memory (PRAM) cell arrangement, the method comprising:

forming a common heater resistor, wherein the heater resistor includes a plurality of first leg portions extending in a first plane and at least one second leg portion extending in a second plane; and

forming a phase change material (PCM) film over an end of each of the plurality of first leg portions and the at least one second leg portion of the heater resistor to form active regions.

53. The method according to claim 52, further comprising:

forming a common bottom electrode;

forming a common via interconnect on the bottom electrode; and

forming a top electrode over the phase change material (PCM) film,

wherein the common heater resistor is formed on the via interconnect.

54. The method according to claim 52, wherein the three-dimensional PRAM cell arrangement is applied in an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the three-dimensional PRAM cell arrangement is integrated.

55. A phase-change random access memory (PRAM) arrangement comprising:

a common heater resistor having a plurality of first leg portions extending in a first plane and at least one second leg portion extending in a second plane; and

a phase change material (PCM) film over an end of each of the plurality of first leg portions and the at least one second leg portion of the heater resistor,

wherein the interface between the phase change material (PCM) film and the end of each of the plurality of first leg portions and the at least one second leg portion of the heater resistor forms active regions.

56. The PRAM arrangement according to claim 55, further comprising:

a common bottom electrode;

a common via interconnect on the bottom electrode; and

a top electrode over the phase change material (PCM) film,

wherein the common heater resistor is on the via interconnect.

57. The PRAM arrangement of claim 55 integrated in at least one semiconductor die.

58. The PRAM arrangement of claim 55, further comprising an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM arrangement is integrated.

59. A phase-change random access memory (PRAM) arrangement, comprising:

a plurality of phase-change random access memory (PRAM) cells, wherein each of the PRAM cells includes;

a heater resistor; and

a phase change material (PCM) formed over and coupled to the heater resistor,

wherein the phase change material (PCM) is common to each of the plurality of phase-change random access memory (PRAM) cells, and

wherein the common phase change material (PCM) has a central portion and a plurality of portions extending from the central portion to the plurality of PRAM cells.

60. The PRAM arrangement according to claim 59, wherein the central portion of the common phase change material (PCM) has a diamond-shape.

61. The PRAM arrangement according to claim 59, further comprising:

a top electrode coupled to the phase change material (PCM),

wherein the top electrode is common to each of the plurality of phase-change random access memory (PRAM) cells, and

wherein the common top electrode has a central portion and a plurality of portions extending from the central portion to the plurality of PRAM cells.

62. The PRAM arrangement according to claim 61, wherein the central portion of the common top electrode has a diamond-shape.

63. The PRAM arrangement according to claim 59, wherein the phase change material (PCM) contacts a portion of a vertical surface of the heater resistor and a portion of a horizontal surface of the heater resistor to form an active region between the heater resistor and the phase change material (PCM).

64. The PRAM arrangement of claim 59 integrated in at least one semiconductor die.

65. The PRAM arrangement of claim 59, further comprising an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM arrangement is integrated.

66. A phase-change random access memory (PRAM) arrangement, comprising:

a plurality of phase-change random access memory (PRAM) cells, wherein each of the PRAM cells includes;

a heater resistor; and

a phase change material (PCM) formed over and coupled to the heater resistor,

wherein the heater resistor is common to each of the plurality of phase-change random access memory (PRAM) cells, and

wherein the common heater resistor has a central portion and a plurality of portions extending from the central portion to the plurality of PRAM cells.

67. The PRAM arrangement according to claim 66, wherein the central portion of the common heater resistor has a diamond-shape.

68. The PRAM arrangement according to claim 66, further comprising:

a bottom electrode coupled to the heater resistor,

wherein the bottom electrode is common to each of the plurality of phase-change random access memory (PRAM) cells, and

wherein the bottom electrode is coupled to the common heater resistor.

69. The PRAM arrangement according to claim 66, wherein the phase change material (PCM) contacts a portion of a vertical surface of the heater resistor and a portion of a horizontal surface of the heater resistor to form an active region between the heater resistor and the phase change material (PCM).

70. The PRAM arrangement of claim 66 integrated in at least one semiconductor die.

71. The PRAM arrangement of claim 66, further comprising an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM arrangement is integrated.

72. A phase-change random access memory (PRAM) cell, comprising:

a resistive means for generating heat; and

a phase change means for allowing phase change coupled to the resistive means;

wherein an active region between the resistive means and the phase change means is defined by a first physical dimension and a second physical dimension of the resistive means.

73. The PRAM cell according to claim 72, further comprising:

a cap means for capping the resistive means except for the active region,

wherein the phase change means is formed over a portion of the cap means.

74. The PRAM cell according to claim 73, wherein the phase change means overlaps the portion of the cap means by a predetermined distance to prevent or reduce etching damage impact on the active region.

75. The PRAM cell according to claim 72, further comprising:

first electrode means for electrically connecting the PRAM cell;

interconnecting means for interconnecting the first electrode to the resistive means, wherein the resistive means is formed over the interconnect means; and

second electrode means for electrically connecting the PRAM cell.

76. The PRAM cell according to claim 72, wherein the PRAM cell is applied in an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM cell is integrated.

77. A method of forming a phase-change random access memory (PRAM) cell, the method comprising:

step for forming a heater resistor; and

step for forming a phase change material (PCM) over an active region of the heater resistor,

wherein the active region of the heater resistor includes a portion of a vertical surface of the heater resistor and a portion of a horizontal surface of the heater resistor.

78. The method according to claim 77, further comprising:

step for forming a cap film over the heater resistor except for the active region of the heater resistor,

wherein the phase change material (PCM) is formed over a portion of the cap film.

79. The method according to claim 78, wherein the phase change material (PCM) overlaps the portion of the cap film by a predetermined distance to prevent or reduce etching damage impact on the active region.

80. The method according to claim 77, further comprising:

step for forming a bottom electrode;

step for forming a via interconnect on the bottom electrode, wherein the heater resistor is formed over the via interconnect; and

step for forming a top electrode over the phase change material (PCM).

81. The method according to claim 77, wherein the PRAM cell is applied in an electronic device, selected from the group consisting of a set top box, music player, video player, entertainment unit, navigation device, communications device, personal digital assistant (PDA), fixed location data unit, and a computer, into which the PRAM cell is integrated.