MOS transistor with laser-patterned metal gate, and method for making the same

• US 8,461,628 B2
• Filed: 08/11/2005
• Issued: 06/11/2013
• Est. Priority Date: 03/18/2005
• Status: Active Grant

• Current Assignee: Ensurge Micropower ASA
• Original Assignee: Kovio Incorporated (Ensurge Micropower ASA)
• Inventors: Choi, Criswell, Rockenberger, Joerg, MacKenzie, J. Devin, Gudeman, Christopher
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): JEFFERSON, QUOVAUNDA
• Application Number:
  US11/203,563
• Publication Number:
  US 20060211187A1
• Time in Patent Office: 2,861 Days
• Field of Search: 438/487, 438/199, 438/618, 438/622, 438/689, 438/690, 438/694, 438/940, 438/685, 438/686, 438/687, 438/688, 438/660, 438/661, 438/662, 438/795, 438/800, 438/FOR.109, 438/FOR.437, 438/FOR.352, 438/FOR.354, 438/FOR.405, 257/202, 257/204, 257/209, 257/388, 257/412, 257/211, 257/E29.158, 257/E29.16, 257/E21.621, 257/E21.625, 257/368, 257/87, 257/E21.028, 257/E21.596, 257/E29.128, 257/E29.134
• US Class Current: 257/213
• CPC Class Codes: H01L 21/28123 Lithography-related aspects, e.g. sub-lithography lengths; Isolation-related aspects, e.g. to solve problems arising at the crossing with the side of the device isolation; Planarisation aspects
• CPC Class Codes: H01L 21/32131 by physical means only
• CPC Class Codes: H01L 21/84 the substrate being other than a semiconductor body, e.g. being an insulating body
• CPC Class Codes: H01L 27/1292 using liquid deposition, e.g. printing
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate

Abstract

A MOS transistor with a laser-patterned metal gate, and methods for its manufacture. The method generally includes forming a layer of metal-containing material on a dielectric film, wherein the dielectric film is on an electrically functional substrate comprising an inorganic semiconductor; laser patterning a metal gate from the metal-containing material layer; and forming source and drain terminals in the inorganic semiconductor in locations adjacent to the metal gate. The transistor generally includes an electrically functional substrate; a dielectric film on at least portions of the electrically functional substrate; a laser patterned metal gate on the dielectric film; and source and drain terminals comprising a doped inorganic semiconductor layer adjacent to the metal gate. The present invention advantageously provides MOS thin film transistors having reliable electrical characteristics quickly, efficiently, and/or at a low cost by eliminating one or more conventional photolithographic steps.

Claims

1. An electronic device, comprising:

a) a substrate;

b) a semiconductor layer on the substrate;

c) a dielectric film on at least portions of said substrate and/or said semiconductor layer;

d) a laser written metal gate on the dielectric film; and

e) source and drain terminals comprising a doped layer on or in said semiconductor layer, substantially adjacent to said laser written metal gate, wherein each of said source and drain terminals has a border closest to said laser written metal gate that is substantially aligned with a border of said laser written metal gate.

2. The electronic device of claim 1, further comprising (i) one or more first conductors electrically connected to each of said source and drain terminals and (ii) a second conductor electrically connected to said laser written metal gate.

3. The electronic device of claim 2, wherein said second conductor comprises at least one conductive and/or barrier layer, and said second conductor contacts a landing pad region of the laser written metal gate.

4. The electronic device of claim 3, wherein said landing pad region has a width of from 1.25 to 4 times a width of said laser written metal gate.

5. The electronic device of claim 2, further comprising a second dielectric and/or a passivation layer over said first and second conductors and said laser written metal gate.

6. The electronic device of claim 1, wherein said substrate and said semiconductor layer comprise an electrically inert substrate and a transistor channel layer thereon.

7. The electronic device of claim 6, wherein said transistor channel layer comprises a lightly doped semiconductor.

8. The electronic device of claim 1, wherein said doped layer comprises an electrically active, polycrystalline Group IVA semiconductor layer.

9. The electronic device of claim 1, wherein said dielectric film has a thickness of from 20 Å

to 400 Å

.

10. The electronic device of claim 1, wherein said laser written metal gate has a width greater than a width of said dielectric film.

11. The electronic device of claim 1, wherein said laser written metal gate has a width of at least 2 microns.

12. The electronic device of claim 1, wherein said laser written metal gate has a width of at least 5 microns.

13. The electronic device of claim 1, wherein said laser written metal gate consists essentially of a metal or a metal alloy.

14. The electronic device of claim 13, wherein said laser written metal gate consists essentially of cured and/or annealed metal nanoparticles.

15. The electronic device of claim 1, wherein said laser written metal gate has a thickness of from 50 nm to 5000 nm.

16. The electronic device of claim 1, wherein said source and drain terminals comprise a heavily doped semiconductor layer.

17. The electronic device of claim 1, wherein said dielectric film has a thickness greater than a thickness of said source and drain terminals.

18. The electronic device of claim 1, wherein said substrate comprises a glass plate, a ceramic plate or disc, a plastic sheet or disc, metal foil, a metal sheet or disc, or a laminated or layered combination thereof.

19. The electronic device of claim 18, wherein said substrate comprises said metal foil and a barrier layer directly thereon.

20. The electronic device of claim 18, wherein said substrate comprises said metal foil and said dielectric layer directly thereon.

21. The electronic device of claim 1, wherein said laser written metal gate comprises a cured and/or annealed metal precursor, said metal precursor comprising at least one photodefinable metal-containing species.

22. The electronic device of claim 1, wherein said laser written metal gate comprises a directly irradiated metal precursor.

23. The electronic device of claim 1, wherein said laser written metal gate is formed by a process comprising directly irradiating a portion of a metal precursor and removing non-irradiated portions of said metal precursor with a developer.

24. An electronic device, comprising:

a) a substrate;

b) a semiconductor layer on the substrate;

c) a dielectric film on at least portions of said substrate and/or said semiconductor layer;

d) a laser written metal gate on the dielectric film, said metal gate having a width of at least 2 microns; and

e) source and drain terminals comprising a doped layer on or in said semiconductor layer, substantially adjacent to said laser written metal gate.

25. The electronic device of claim 24, wherein each of said source and drain terminals has a border closest to said laser written metal gate that is substantially aligned with a border of said laser written metal gate.

26. The electronic device of claim 24, further comprising (i) one or more first conductors electrically connected to each of said source and drain terminals and (ii) a second conductor electrically connected to said laser written gate.

27. The electronic device of claim 26, wherein said second conductor comprises at least one conductive and/or barrier layer, and said second conductor contacts a landing pad region of the laser written metal gate.

28. The electronic device of claim 27, wherein said landing pad region has a width of from 1.25 to 4 times a width of said laser written metal gate.

29. The electronic device of claim 26, further comprising a second dielectric and/or a passivation layer over said first and second conductors and said laser written metal gate.

30. The electronic device of claim 24, wherein said substrate and said semiconductor layer comprise an electrically inert substrate and a transistor channel layer thereon.

31. The electronic device of claim 30, wherein said transistor channel layer comprises a lightly doped semiconductor.

32. The electronic device of claim 24, wherein said doped layer comprises an electrically active, polycrystalline Group IVA semiconductor layer.

33. The electronic device of claim 24, wherein said dielectric film has a thickness of from 20 Å

to 400 Å

.

34. The electronic device of claim 24, wherein said laser written metal gate has a width greater than a width of said dielectric film.

35. The electronic device of claim 24, wherein said laser written metal gate has a width of at least 5 microns.

36. The electronic device of claim 24, wherein said laser written metal gate consists essentially of a metal or a metal alloy.

37. The electronic device of claim 36, wherein said laser written metal gate consists essentially of cured and/or annealed metal nanoparticles.

38. The electronic device of claim 24, wherein said laser written metal gate has a thickness of from 50 nm to 5000 nm.

39. The electronic device of claim 24, wherein said source and drain terminals comprise a heavily doped semiconductor layer.

40. The electronic device of claim 24, wherein said dielectric film has a thickness greater than a thickness of said source and drain terminals.

41. The electronic device of claim 24, wherein said substrate comprises a glass plate, a ceramic plate or disc, a plastic sheet or disc, metal foil, a metal sheet or disc, or a laminated or layered combination thereof

42. The electronic device of claim 41, wherein said substrate comprises said metal foil and a barrier layer thereon.

43. The electronic device of claim 41, wherein said substrate comprises said metal foil and said dielectric layer thereon.

44. The electronic device of claim 24, wherein said laser written metal gate comprises a cured and/or annealed metal precursor, said metal precursor comprising at least one photodefinable metal-containing species.

45. The electronic device of claim 24, wherein said laser written metal gate comprises a directly irradiated metal precursor.

46. The electronic device of claim 24, wherein said laser written metal gate is formed by a process comprising directly irradiating a portion of a metal precursor and removing non-irradiated portions of said metal precursor with a developer.