Light emitting device with small size and large density

• US 10,566,317 B2
• Filed: 05/20/2018
• Issued: 02/18/2020
• Est. Priority Date: 05/20/2018
• Status: Active Grant

• Current Assignee: Black Peak LLC (Black Peak Holdings Pty Ltd.)
• Original Assignee: Black Peak LLC (Black Peak Holdings Pty Ltd.)
• Inventors: Herner, Scott Brad
• Primary Examiner(s): Mandala, Michelle
• Assistant Examiner(s): Klein, Jordan M
• Application Number:
  US15/984,370
• Publication Number:
  US 20190355702A1
• Time in Patent Office: 639 Days
• Field of Search: None
• CPC Class Codes: H01L 21/28518 the conductive layers comprising silicides H01L21/28537 takes precedence
• CPC Class Codes: H01L 21/76898 formed through a semiconductor substrate
• CPC Class Codes: H01L 21/823475 interconnection or wiring or contact manufacturing related aspects
• CPC Class Codes: H01L 23/481 Internal lead connections, e.g. via connections, feedthrough structures
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 27/0688 Integrated circuits having a three-dimensional layout
• CPC Class Codes: H01L 27/088 the components being field-effect transistors with insulated gate
• CPC Class Codes: H01L 29/45 Ohmic electrodes
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/60 : Reflective elements
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

This application describes a light emitting device, an assembly of light emitting devices, a display comprising assemblies of light emitting devices, and methods of fabricating same. The light emitting device comprises a transistor, an LED that at least partially overlies the transistor, a reflector layer disposed between the LED and transistor, and conductive wires that connect electrically the transistor to the LED. The assembly comprises a plurality of light emitting devices, and the display comprises a plurality of assemblies.

Claims

1. A light emitting device comprising:

a transistor substrate having a top surface and a bottom surface, wherein the top surface comprises a plurality of conductive regions;

a plurality of conductive wires, wherein each conductive wire of the plurality extends through the transistor substrate from one of the conductive regions of the plurality of conductive regions to the bottom surface of the transistor substrate;

a transistor, wherein the transistor is formed in the top surface of the transistor substrate;

an LED having a surface area, wherein the LED at least partially overlies the transistor and wherein the LED comprises gallium nitride, indium gallium nitride, indium arsenide, aluminum gallium arsenide, gallium arsenide, gallium phosphide, gallium arsenide phosphide, or aluminum indium gallium phosphide; and

a reflector layer, wherein the reflector layer is disposed between the LED and the transistor.

2. The light emitting device of claim 1, further comprising an interconnect, wherein the interconnect connects the LED to the transistor electrically.

3. The light emitting device of claim 2, wherein at least a portion of the interconnect is substantially transparent to light of wavelength 450 to 730 nm.

4. The light emitting device of claim 1, further comprising a wavelength-converting layer, wherein the wavelength-converting layer partially overlies the LED.

5. The light emitting device of claim 4, wherein the wavelength-converting layer comprises phosphor particles or quantum dots.

6. The light emitting device of claim 1, further comprising a backboard, wherein the backboard comprises a plurality of metal interconnects, and wherein at least one of the metal interconnects is connected electrically to the transistor.

7. The light emitting device of claim 6, wherein the backboard is a printed circuit board or an interposer.

8. The light emitting device of claim 1, wherein a transparent conductive layer is disposed on the LED.

9. The light emitting device of claim 8, wherein the transparent conductive layer comprises indium tin oxide, fluorine tin oxide, or aluminum zinc oxide.

10. The light emitting device of claim 1, wherein the transistor comprises single crystal silicon.

11. The light emitting device of claim 1, wherein at least some of the conductive regions further comprise a silicide layer.

12. The light emitting device of claim 1, wherein the transistor substrate further comprises an etch-stop layer.

13. The light emitting device of claim 1, wherein the transistor substrate has a thickness, and wherein the thickness is less than 20 microns.

14. The light emitting device of claim 1, wherein the surface area of the LED is 40,000 square microns or less.

15. The light emitting device of claim 1, wherein the surface area of the LED is 1,000 square microns or less.

16. The light emitting device of claim 1, wherein the surface area of the LED is 100 square microns or less.

17. The light emitting device of claim 1, wherein the reflector layer comprises a Bragg reflector.

18. The light emitting device of claim 1, wherein the plurality of conductive wires comprises titanium, titanium nitride, tantalum, tantalum nitride, chrome, indium, tungsten, copper, or aluminum.

19. The light emitting device of claim 2, wherein the interconnect comprises titanium, titanium nitride, tantalum, tantalum nitride, tungsten, copper, aluminum, indium tin oxide, aluminum zinc oxide, or fluorine tin oxide.

20. A light emitting assembly, comprising:

a transistor substrate having a top surface and a bottom surface, wherein the top surface comprises a plurality of conductive regions;

a plurality of conductive wires, wherein each conductive wire extends through the transistor substrate from a conductive region of the plurality of conductive regions to the bottom surface of the transistor substrate;

a plurality of transistors, wherein each transistor is formed in the top surface of the transistor substrate;

a plurality of LEDs, wherein each LED has a surface area, wherein each LED at least partially overlies a transistor of the plurality of transistors, and wherein the plurality of LEDs comprises gallium nitride, indium gallium nitride, indium arsenide, aluminum gallium arsenide, gallium arsenide, gallium phosphide, gallium arsenide phosphide, or aluminum indium gallium phosphide; and

at least one reflector layer, wherein the at least one reflector layer is disposed between one LED of the plurality of LEDs and a transistor of the plurality of transistors.

21. The light emitting assembly of claim 20, further comprising a plurality of interconnects, wherein each interconnect electrically connects an LED of the plurality of LEDS to a transistor of the plurality of transistors.

22. The light emitting assembly of claim 21, wherein at least portions of the plurality of interconnects are substantially transparent to light of wavelength 450 to 730 nm.

23. The light emitting assembly of claim 20, wherein a transparent conductive layer is disposed on the plurality of LEDs.

24. The light emitting assembly of claim 23, wherein the transparent conductive layer comprises indium tin oxide, fluorine tin Wide, or aluminum zinc oxide.

25. The light emitting assembly of claim 20, further comprising a plurality of wavelength-converting layers, wherein at least one of the wavelength-converting layers at least partially overlies one LED of the plurality of LEDs.

26. The light emitting assembly of claim 25, wherein the plurality of wavelength-converting layers comprises phosphor particles or quantum dots.

27. The light emitting assembly of claim 25, wherein the plurality of wavelength-converting layers comprises at least a first wavelength-converting layer that emits light with a dominant wavelength between 500 and 550 nm and a second wavelength-converting layer that emits light with a dominant wavelength between 610 and 730 nm.

28. The light emitting assembly of claim 20, further comprising side reflectors, wherein the side reflectors are disposed between adjacent LEDs of the plurality of LEDs and prevent light from neighboring light emitting devices from mutually interfering.

29. The light emitting assembly of claim 28, wherein the side reflectors comprise aluminum, silver, or metal oxide.

30. The light emitting assembly of claim 20, wherein the transistor substrate has a thickness, and wherein the thickness is less than 20 microns.

31. The light emitting assembly of claim 20, wherein at least some of the conductive regions further comprise a silicide layer.

32. The light emitting assembly of claim 20, wherein the light emitting assembly is attached to a backboard, the backboard comprising a plurality of metal interconnects, and wherein at least one of the metal interconnects is connected electrically to one of the transistors.

33. The light emitting assembly of claim 32, wherein the backboard is a printed circuit board or an interposer.

34. The light emitting assembly of claim 20, wherein the plurality of transistors comprises single crystal silicon.

35. The light emitting assembly of claim 20, wherein the transistor substrate further comprises an etch-stop layer.

36. The light emitting assembly of claim 20, wherein the surface area of at least one LED of the plurality of LEDs is 40,000 square microns or less.

37. The light emitting assembly of claim 20, wherein the surface area of at least one LED of the plurality of LEDs is 1,000 square microns or less.

38. The light emitting assembly of claim 20, wherein the surface area of at least one LED of the plurality of LEDs is 100 square microns or less.

39. The light emitting assembly of claim 20, wherein the plurality of reflector layers comprises a Bragg reflector.

40. A display apparatus comprising:

a plurality of light emitting assemblies, wherein each assembly comprises;

a transistor substrate having a top surface and a bottom surface, wherein the top surface comprises a plurality of conductive regions;

a plurality of conductive wires, wherein each conductive wire extends through the transistor substrate from a conductive region of the plurality of conductive regions to the bottom surface of the transistor substrate;

a plurality of transistors, wherein each transistor is formed in the top surface of the transistor substrate;

a plurality of LEDs, wherein each LED has a surface area, wherein each LED is connected electrically to a transistor of the plurality of transistors, and wherein the plurality of LEDs comprises gallium nitride, indium gallium nitride, indium arsenide, aluminum gallium arsenide, gallium arsenide, gallium phosphide, gallium arsenide phosphide, or aluminum indium gallium phosphide;

at least one reflector layer, wherein the at least one reflector layer is disposed between one LED of the plurality of LEDs and a transistor of the plurality of transistors; and

a backboard, wherein the backboard comprises a plurality of metal interconnects, and wherein at least one of the metal interconnects is connected electrically to at least one of the transistors of the plurality of transistors.

41. The display apparatus of claim 40 wherein at least some of the conductive regions further comprise a silicide layer.

42. The display apparatus of claim 40 wherein the plurality of conductive wires comprises titanium, titanium nitride, tantalum, tantalum nitride, chrome, indium, tungsten, copper, or aluminum.

43. The display apparatus of claim 40, further comprising a plurality of wavelength-converting layers, wherein at least one wavelength-converting layer overlies one LED of the plurality of LEDs.

44. The display apparatus of claim 43, wherein the plurality of wavelength-converting layers comprises phosphor particles or quantum dots.

45. The display apparatus of claim 43, wherein the plurality of wavelength-converting layers comprises at least a first wavelength-converting layer and a second wavelength-converting layer.

46. The display apparatus of claim 45, wherein the first wavelength-converting layer emits light with a dominant wavelength between 500 and 550 nm and the second wavelength-converting layer emits light with a dominant wavelength between 610 and 730 nm.

47. The display apparatus of claim 40, wherein the backboard is a printed circuit board or an interposer.

48. The display apparatus of claim 40, wherein the transistor substrate has a thickness, and wherein the thickness is less than 20 microns.

49. The display apparatus of claim 40, wherein the plurality of transistors comprises single crystal silicon.

50. The display apparatus of claim 40, wherein the transistor substrate further comprises an etch-stop layer.

51. The display apparatus of claim 40, further comprising side reflectors, wherein the side reflectors are disposed between adjacent LEDs of the plurality of light emitting devices and prevent light from neighboring light emitting devices from mutually interfering.

52. The display apparatus of claim 51, where in the side reflectors comprise aluminum, silver, or metal oxide.

53. The display apparatus of claim 40, wherein the surface area of at least one LED of the plurality of LEDs is 40,000 square microns or less.

54. The display apparatus of claim 40, wherein the surface area of at least one LED of the plurality of LEDs is 1,000 square microns or less.

55. The display apparatus of claim 40, wherein the surface area of at least one LED of the plurality of LEDs is 100 square microns or less.

56. The display apparatus of claim 40, wherein the reflector layers comprise a Bragg reflector.