Process and structure of an integrated vacuum microelectronic device

• US 5,203,731 A
• Filed: 03/05/1992
• Issued: 04/20/1993
• Est. Priority Date: 07/18/1990
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Zimmerman, Steven M.
• Primary Examiner(s): Seidel, Richard K.
• Assistant Examiner(s): Knapp, Jeffrey J.
• Application Number:
  US07/847,153
• Time in Patent Office: 411 Days
• Field of Search: 445/24, 445/50, 445/51, 437/927
• US Class Current: 445/24
• CPC Class Codes: H01J 21/105 with microengineered cathode and control electrodes, e.g. Spindt-type
• CPC Class Codes: H01J 2201/30457 Diamond
• CPC Class Codes: H01J 9/025 of field emission cathodes

Abstract

The present invention relates generally to a new integrated Vacuum Microelectronic Device (VMD) and a method for making the same. Vacuum Microelectronic Devices require several unique three dimensional structures: a sharp field emission tip, accurate alignment of the tip inside a control grid structure in a vacuum environment, and an anode to collect electrons emitted by the tip. Also disclosed is a new structure and a process for forming diodes, triodes, tetrodes, pentodes and other similar structures. The final structure made can also be connected to other similar VMD devices or to other electronic devices.

Claims

1. A process of making at least one integrated vacuum microelectronic device comprising the steps of:

a) providing at least one hole in a substrate having at least one electrically conductive material,

b) filling at least a portion of said hole with at least one material sufficiently to form a cusp,

c) depositing at least one layer of a material which is capable of emitting electrons under the influence of an electrical field, and filling at least a portion of said cusp to form a tip,

d) providing at least one access hole to help facilitate the removal of material underneath the cusp, and

e) removing the material underneath said cusp to expose at least a portion of said tip of said electron-emitting material and at least a portion of said electrically conductive material in said substrate, thereby forming said at least one integrated vacuum microelectronic device.

2. The process of making an integrated vacuum microelectronic device of claim 1, wherein said substrate comprises of at least one insulative layer, and wherein said insulative layer separates said electrically conductive material from said electron-emitting material.

3. The process of making an integrated vacuum microelectronic device of claim 1, wherein said substrate comprises of a multilayered structure.

4. The process of making an integrated vacuum microelectronic device of claim 3, wherein said multi-layered structure comprises of alternating layers of insulative and electrically conductive material.

5. The process of making an integrated vacuum microelectronic device of claim 1, wherein said hole in step (a) is formed by a process selected from a group comprising, ablation, drilling, etching, ion milling, lift-off or molding.

6. The process of making an integrated vacuum microelectronic device of claim 1, wherein said hole in step (a) is etched, using etching techniques selected from a group comprising anisotropic etching, ion beam etching, isotropic etching, reactive ion etching, plasma etching or wet etching.

7. The process of making an integrated vacuum microelectronic device of claim 1, wherein said hole has a profile where the dimensions of the hole are constant with depth.

8. The process of making an integrated vacuum microelectronic device of claim 1, wherein said hole has a profile where the dimensions of the hole varies with depth.

9. The process of making an integrated vacuum microelectronic device of claim 1, wherein said cusp forming material is conformally deposited.

10. The process of making an integrated vacuum microelectronic device of claim 1, wherein said cusp forming material is an insulative material.

11. The process of making an integrated vacuum microelectronic device of claim 1, wherein said cusp forming material comprises of multilayers.

12. The process of making an integrated vacuum microelectronic device of claim 1, wherein said electron-emitting material is a single layered material.

13. The process of making an integrated vacuum microelectronic device of claim 1, wherein said electron-emitting material is multilayered.

14. The process of making an integrated vacuum microelectronic device of claim 1, wherein in step (d) said access hole is formed by a process selected from a group comprising, ablation, drilling, etching, lift-off or ion milling.

15. The process of making an integrated vacuum microelectronic device of claim 1, wherein in step (d) said access hole is etched, using etching techniques selected from a group comprising anisotropic etching, ion beam etching, isotropic etching, reactive ion etching, plasma etching or wet etching.

16. The process of making an integrated vacuum microelectronic device of claim 1, wherein in step (e) said material under the cusp is removed by a process selected from the group comprising, dissolution or etching.

17. The process of making an integrated vacuum microelectronic device of claim 1, wherein a barrier layer is formed prior to the deposition of said electron-emitting material.

18. The process of making an integrated vacuum microelectronic device of claim 17, wherein said barrier layer is selectively removed.

19. The process of making an integrated vacuum microelectronic device of claim 1, wherein said tip is coated with an electron-emitting material.

20. The process of making an integrated vacuum microelectronic device of claim 1, wherein said tip is selectively sharpened by a process selected from a group comprising slow isotropic etching or oxidation.

30. The process of making an integrated vacuum microelectronic device of claim 1, wherein in step a) the shape of said at least one hole in said substrate is a narrow elongated segment so that in step e) the shape of said tip of said electron-emitting material has a blade profile.

31. The process of making an integrated vacuum microelectronic device of claim 1, wherein the area underneath said tip is provided with at least one high ionization potential gas.

32. The process of making an integrated vacuum microelectronic device of claim 31, wherein said high ionization potential gas is helium.

33. The process of making an integrated vacuum microelectronic device of claim 1, wherein said electron-emitting material is selected from a group consisting of Mo, W, Ta, Re, Pt, Au, Ag, Al, Cu, Nb, Ni, Cr, Ti, Zr, Hf and allows thereof or solid solutions containing two or more of these elements.

34. The process of making an integrated vacuum microelectronic device of claim 1, wherein said electron-emitting material is selected from a group consisting of doped and undoped semiconductors.

35. The process of making an integrated vacuum microelectronic device of claim 1, wherein said insulating material is selected from a group consisting of sapphire, glass or oxides of Si, Al, Mg and Ce.

36. The process of making an integrated vacuum microelectronic device of claim 1, wherein after step c) a second material is deposited on said at least one layer of said electron-emitting material.

37. The process of making an integrated vacuum microelectronic device of claim 1, wherein said substrate further comprises at least one semiconductor material.

38. The process of making an integrated vacuum microelectronic device of claim 1, wherein said substrate of step a) is formed on an insulative substrate.

39. The process of making an integrated vacuum microelectronic device of claim 38, wherein the material for said substrate is selected from a group comprising Mo, W, Ta, Re, Pt, Au, Ag, Al, Cu, Nb, Ni, Cr, Ti, Zr, Hf and allows thereof or solid solutions containing two or more of these elements.

21. A process of making at least one integrated vacuum microelectronic device comprising the steps of:

a) providing at least one hole in a substrate having at least one electrically conductive material,

b) depositing at least one insulative material and filling said hole to form a cusp,

c) depositing at least one layer of a material which is capable of emitting electrons under the influence of an electrical field, and filling at least a portion of said cusp to form a tip,

d) providing at least one access hole to help facilitate the removal of material underneath the cusp, and

e) through said access hole removing all of said material in said hole and exposing at least a portion of said tip of said electron-emitting material and at least a portion of said electrically conductive material in said substrate, thereby forming said at least one integrated vacuum microelectronic device.

22. The process of making, an integrated vacuum microelectronic device of claim 21, wherein said substrate comprises of a conductive material.

23. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate comprises of a conductive material over an insulative material such that said conductive material. is thick enough to contain said hole

24. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate comprises of two insulating materials separated by a conductive material, wherein one of said insulting materials is thick enough to form said hole and wherein said hole exposes at least a portion of said conductive material.

25. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate comprises of an insulative material which is thick enough to form said hole, and wherein said conductive material is conformally deposited in said hole prior to the deposition of said insulative material of step (b).

26. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate comprises of at least two conductive materials separated by at least one insulative material and wherein said hole penetrates one conductive material one insulative material and exposes at least a portion of a second conductive material.

27. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate comprises of an insulative base material and having least two conductive materials separated by at least one insulative material and wherein said hole penetrates one conductive material one insulative material and exposes at least a portion of a second conductive material.

28. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate comprises of a conductive base material and further having a plurality of electrically conductive material over said substrate, such that each of said electrically conductive material is separated by an insulative material, wherein said hole penetrates all of said conductive materials and said insulative material and exposes at least a portion of said base conductive material.

29. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate comprises of a conductive base material over an insulative base material and further having a plurality of electrically conductive material over said substrate, such that each of said electrically conductive material is separated by an insulative material, wherein said hole penetrates all of said conductive materials and said insulative material and exposes at least a portion of said base conductive material.

40. The process of making an integrated vacuum microelectronic device of claim 21, wherein in step a) the shape of said at least one hole in said substrate is a narrow elongated segment so that in step e) the shape of said tip of said electron-emitting material has a blade profile.

41. The process of making an integrated vacuum microelectronic device of claim 21, wherein the area underneath said tip is provided with at least one high ionization potential gas.

42. The process of making an integrated vacuum microelectronic device of claim 41, wherein said high ionization potential gas is helium.

43. The process of making an integrated vacuum microelectronic device of claim 21, wherein said electron-emitting material is selected from a group consisting of Mo, W, Ta, Re, Pt, Au, Ag, Al, Cu, Nb, Ni, Cr, Ti, Zr, Hf and allows thereof or solid solutions containing two or more of these elements.

44. The process of making an integrated vacuum microelectronic device of claim 21, wherein said electron-emitting material is selected from a group consisting of doped and undoped semiconductors.

45. The process of making an integrated vacuum microelectronic device of claim 21, wherein said insulating material is selected from a group consisting of sapphire, glass or oxides of Si, Al, Mg and Ce.

46. The process of making an integrated vacuum microelectronic device of claim 21, wherein after step c) a second material is deposited on said at least one layer of said electron-emitting material.

47. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate further comprises at least one semiconductor material.

48. The process of making an integrated vacuum microelectronic device of claim 21, wherein said substrate of step a) is formed on an insulative substrate.

49. The process of making an integrated vacuum microelectronic device of claim 48, wherein the material for said substrate is selected from a group comprising Mo, W, Ta, Re, Pt, Au, Ag, Al, Cu, Nb, Ni, Cr, Ti, Zr, Hf and allows thereof or solid solutions containing two or more of these elements.