Method of Fabricating Optical Devices Using Laser Treatment

• US 20130234111A1
• Filed: 11/09/2010
• Published: 09/12/2013
• Est. Priority Date: 11/09/2010
• Status: Active Grant

• Current Assignee: Kyocera SLD Laser Incorporated (Kyocera Corporation)
• Original Assignee: Soraa, Inc.
• Inventors: Pfister, Nicholas J., Raring, James W., Schmidt, Mathew
• Granted Patent: US 9,048,170 B2
• Time in Patent Office: Days
• US Class Current: 257/14
• CPC Class Codes: H01L 29/20 including, apart from doping materials or other impurities, only AIIIBV compounds
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 5/0014 Measuring characteristics or properties thereof measuring techniques per se G01J, G01K, G01N, G01R
• CPC Class Codes: H01S 5/0202 Cleaving
• CPC Class Codes: H01S 5/0203 Etching
• CPC Class Codes: H01S 5/0421 characterised by the semiconducting contacting layers electrodes H01S5/0425
• CPC Class Codes: H01S 5/2013 MQW barrier reflection layers
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/3013 AIIIBV compounds
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

A method for forming optical devices. The method includes providing a gallium nitride substrate member having a crystalline surface region and a backside region. The method also includes subjecting the backside region to a laser scribing process to form a plurality of scribe regions on the backside region and forming a metallization material overlying the backside region including the plurality of scribe regions. The method removes at least one optical device using at least one of the scribe regions.

Claims

1. An optical device comprising:

a gallium and nitrogen containing substrate member having a crystalline surface region and a backside region;

a laser stripe region overlying a portion of the crystalline surface region;

at least one laser scribe line within a spatial region of the backside region and underlying at least a portion the laser stripe region; and

a metallization material overlying the backside region and one or more portions of the at least one laser scribe line.

2. The device of claim 1 wherein the metallization material comprises aluminum material.

3. The device of claim 1 wherein the metallization material comprises a gold material.

4. The device of claim 1 wherein the metallization material comprises a gold material and a nickel material.

6. The device of claim 1 wherein the metal contact is an n-type metal contact.

7. The device of claim 1 further comprising an n-type gallium nitride region overlying the crystalline surface region, an active region overlying the n-type gallium nitride region, and the laser stripe region overlying the active region.

8. The device of claim 7 wherein the active region comprises one to twenty quantum well regions, and is characterized by a thickness of 10 Angstroms to about 50 Angstroms.

9. The device of claim 7 wherein the active region comprises one to twenty quantum well regions, and is characterized by a thickness of 50 Angstroms to about 100 Angstroms.

10. The device of claim 7 wherein the active region comprises an electron blocking region.

11. The device of claim 7 wherein the active region comprises by a separate confinement hetero-structure.

48. The device of claim 1, wherein the at least one laser scribe line is parallel to the laser stripe region.

49. The device of claim 1, wherein the at least one laser scribe line is 3 μ

m to 5 μ

m deep.

50. The device of claim 1, wherein the metallization material comprises a n-type contact.

51. The device of claim 1, wherein the substrate is a nonpolar or a semipolar substrate.

52. The device of claim 1, wherein the substrate is an m-plane substrate.

53. The device of claim 1, wherein the at least one laser stripe line is substantially parallel to the c-direction.

54. The device of claim 1, wherein the at least one laser scribe line comprises one or more annealed portions of the gallium nitride substrate.

55. The device of claim 1, wherein the at least one laser scribe line comprises a higher impurity region within a vicinity of the at least one laser scribe line.

56. The device of claim 1, wherein the metallization material overlying the one or more portions of the at least one laser scribe line includes edges of the scribe region.

57. The device of claim 1, wherein each of the one or more laser scribe lines comprises a recessed region extending partially through a thickness of the gallium nitride substrate.

58. The device of claim 1, wherein the optical device comprises a light emitting diode device.

59. The device of claim 1, wherein the optical device comprises a laser device.

60. The device of claim 1, wherein the crystalline surface region is configured in a non-polar orientation.

61. The device of claim 1, wherein the crystalline surface region is configured in a semi-polar orientation.

62. The device of claim 1, wherein the crystalline surface region is configured in an m-plane orientation having a +/−

6 degree off-cut.

63. The device of claim 1, wherein the crystalline surface region is configured in a {20-21} orientation.

64. The device of claim 1, wherein the at least one laser scribe line comprises multiple laser scribe lines wherein each of the laser scribe lines is arranged in a parallel manner.

5. (canceled)

12. A method for forming optical devices comprising:

providing a gallium nitride substrate member having a crystalline surface region and a backside region;

subjecting the backside region to a laser scribing process to form a plurality of scribe regions on the backside region;

forming a metallization material overlying the backside region including the plurality of scribe regions; and

removing at least one optical device using at least one of the scribe regions.

13. The method of claim 12 further comprising subjecting the backside region including the plurality of scribe regions to a treatment process to remove native oxide from the backside region.

14. The method of claim 12 further comprising subjecting the backside region including the plurality of scribe regions to a treatment process to remove one or more particles of metallization or laser slag from a vicinity of the scribe region.

15. The method of claim 14 wherein the treatment process comprises an HCl etch process.

16. The method of claim 12 wherein the removing comprises one or more singulation processes.

17. The method of claim 12 wherein the metallization comprises an Al/Ni/Au stack.

18. The method of claim 12 wherein the metallization comprises an Al/Pt/Au stack.

19. The method of claim 12 wherein the metallization comprises and Ti/Pt/Au stack.

20. The method of claim 12 further comprising lapping and polishing the backside region before the laser scribing process.

21. The method of claim 12 wherein the metallization material is an re-contact region having a desired resistivity.

22. The method of claim 12 wherein the optical device is characterized by an operating voltage of less than 3.5V.

23. The method of claim 12 wherein the optical device is characterized by an operating voltage of less than 4.5V.

24. The method of claim 12 wherein the optical device is characterized by an operating voltage of less than 5.5V.

25. The method of claim 12 wherein the optical device is characterized by an operating voltage of less than 6.5V.

26. The method of claim 12 wherein the optical device is characterized by an operating voltage of less than 7.5V.

27. The method of claim 12 wherein the laser scribing process anneals one or more portions of the gallium nitride substrate.

28. The method of claim 12 wherein the laser scribing process causes formation of a higher impurity region within a vicinity of one or more scribe regions.

29. The method of claim 12 wherein the metallization material forms overlying each of the scribe regions including edges of the scribe region.

30. The method of claim 12 wherein each of the scribe regions forms a recessed region extending partially through a thickness of the gallium nitride substrate.

31. A method for forming optical devices comprising:

providing a gallium nitride substrate member having a crystalline surface region and a backside region;

forming a metallization material overlying the backside region including the plurality of scribe regions;

subjecting the backside region to a laser scribing process to form a plurality of scribe regions on the backside region; and

removing at least one optical device using at least one of the scribe regions.

32. The method of claim 31 wherein the optical device comprises a light emitting diode device.

33. The method of claim 31 wherein the optical device comprises a laser device.

34. The method of claim 31 wherein the crystalline surface region is configured in a non-polar orientation.

35. The method of claim 31 wherein the crystalline surface region is configured in a semi-polar orientation.

36. The method of claim 31 wherein the crystalline surface region is configured in an m-plane orientation having a +/−

6 degree off-cut.

37. The method of claim 31 wherein the crystalline surface region is configured in a {20-21} orientation.

38. The method of claim 31 wherein each of the scribe lines are arranged in a parallel manner.

39. The method of claim 31 wherein one or more of the scribe lines is arranged in at least one spatial configuration including an annular segment, a circular segment, a straight line segment, an irregular line segment, or other combinations.

40. The method of claim 31 wherein the laser scribing process is provided form a 355 nm UV source.

41. A method for forming optical devices comprising:

providing a gallium nitride substrate member having a crystalline surface region and a backside region, the crystalline surface region configured in a non-polar or semi-polar orientation;

forming one or more active regions configured to emit electromagnetic radiation for an optical device;

forming a metallization material overlying a surface region;

subjecting the surface region to a laser treatment process to change an operating voltage of the optical device from a first value to a second value, the second value being less than the first value by at least 10 percent and causing formation of at least one scribe region on the surface region; and

removing at least the optical device using at least the scribe region.

42. The method of claim 41 wherein the forming of the metallization material is provided before or after the laser treatment process.

43. The method of claim 41 wherein the removing process further comprising a breaking process.

44. The method of claim 41 wherein the surface region comprises at least the back side region or the front side region.

45. The method of claim 41 wherein the electromagnetic radiation comprises substantially 405 nm emission.

46. The method of claim 41 wherein the electromagnetic radiation comprises substantially 485 nm emission.

47. The method of claim 41 wherein the electromagnetic radiation comprises substantially a range from about 495 nm to about 535 nm emission.