Thin film LED

• US 6,744,196 B1
• Filed: 12/11/2002
• Issued: 06/01/2004
• Est. Priority Date: 12/11/2002
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: Oriol, Inc.
• Inventors: Jeon, Hyeong Tag
• Primary Examiner(s): Patel, Vip
• Application Number:
  US10/316,004
• Time in Patent Office: 538 Days
• Field of Search: 313/498, 313/506, 313/512
• US Class Current: 313/498
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/4918 being disposed on at least two different sides of the body, e.g. dual array
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• 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 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material

Abstract

Light emitting LEDs devices comprised of LED chips that emit light at a first wavelength, and a tinted thin film layer over the LED chip that changes the color of the emitted light. For example, a blue-light emitting LED chip can be used to produce white light. The tinted thin film layer beneficially consists of ZnSe, CeO₂, Al₂O₃, or Y₂O₃:Ce that is deposited using a chemical vapor deposition process, such as metal organic chemical vapor deposition (MOCVD), atomic layer chemical vapor deposition (ALD), plasma enhanced MOCVD, plasma enhanced ALD, and/or photo enhanced CVD. Suitable CVD precursors include Alkoxide, β-dikeonate, Metalloscene, Alkys, DMZn, DEZe, H₂Se, DMSe, TbuSe, and DESe.

Claims

1. A light emitting diode (LED), comprising:

an LED chip having a first electrical contact and a second electrical contact, wherein the LED chip emits blue light having a first wavelength in response to applied electrical power; and

a yellow thin-film layer over the LED chip;

wherein the yellow thin-film layer and the blue light interact to form light having a second wavelength.

2. An LED according to claim 1, wherein the yellow thin-film layer is selected from a group consisting of ZnSe, CeO₂, Al₂O₃, and Y₂O₃:

Ce.

3. An LED according to claim 1, further including an inner passivation layer disposed between the yellow thin-film layer and the LED chip.

4. An LED according to claim 1, wherein the yellow thin-film layer and the blue light interact to form white light.

5. An LED according to claim 1, further comprising an outer passivation layer over the yellow thin-film layer.

6. An LED according to claim 1, further comprising a first bonding wire connected to the first electrical contact and a second bonding wire connected to the second electrical contact.

7. An LED according to claim 1, wherein the LED chip has a lateral topology structure.

8. An LED according to claim 7, wherein the LED chip includes:

a substrate;

an n-type GaN structure on a second surface of the substrate;

an active layer having at least one quantum well on the n-GaN structure;

a p-type GaN layer on the active layer;

a transparent conductive layer on the p-type GaN layer;

a p-type electrical contact on the transparent conductive layer; and

an n-type electrical contact on the n-type GaN structure.

9. An LED according to claim 8, wherein the p-type electrical contact forms the first electrical contact and the n-type electrical contact forms the second electrical contact.

10. An LED according to claim 8, wherein the n-type GaN structure includes an n-type GaN buffer layer.

11. An LED according to claim 8, wherein the substrate is sapphire.

12. An LED according to claim 1, wherein the LED chip has a vertical topology structure.

13. An LED according to claim 12, wherein the LED chip includes:

an n-type GaN structure;

an n-type electrical contact adjacent a surface of the n-type GaN structure;

an active layer having at least one quantum well on the n-type GaN structure;

a p-type GaN layer on the active layer;

a transparent conductive layer on the p-type GaN layer; and

a p-type electrical contact on the transparent conductive layer.

14. An LED according to claim 13, wherein the p-type electrical contact forms the first electrical contact and the n-type electrical contact forms the second electrical contact.

15. An LED according to claim 13, wherein the n-type GaN structure includes an n-type GaN buffer layer.

16. An LED according to claim 3, wherein the inner passivation includes SiO₂.

17. An LED according to claim 3, wherein the inner passivation includes Si_xN_y.

18. An LED according to claim 1, further including a package the environmentally protects the LED chip.

19. A method of fabricating a white-light LED, comprising:

procuring an LED chip that emits blue-light at a first wavelength, wherein the LED chip includes a first electrical contact and a second electrical contact;

forming a yellow thin-film layer over the LED chip; and

producing light having at least a second wavelength by passing electrical current through the first and second electrical contacts.

20. A method of fabricating a white-light LED according to claim 19, wherein forming the yellow thin-film layer is performed by depositing a material selected from a group consisting of ZnSe, CeO₂, Al₂O₃, and Y₂O₃:

Ce.

21. A method of fabricating a white-light LED according to claim 20, wherein forming the yellow thin-film layer is performed by chemical vapor deposition.

22. A method of fabricating a white-light LED according to claim 21, wherein the chemical vapor deposition process is selected from a group consisting of metal organic chemical vapor deposition (MOCVD), atomic layer chemical vapor deposition (ALD), plasma enhanced MOCVD, plasma enhanced ALD, low pressure CVD, photo enhanced CVD and CVD.

23. A method of fabricating a white-light LED according to claim 21, wherein chemical vapor deposition is performed using a metal precursor of a metal halide.

24. A method of fabricating a white-light LED according to claim 21, wherein chemical vapor deposition process is performed using a metal organic precursor.

25. A method of fabricating a white-light LED according to claim 21, wherein chemical vapor deposition is performed using a material selected from a group consisting of Alkoxide, β

-dikeonate, Metalloscene, Alkys, DMZn, DEZn, H₂Se, DMSe, TbuSe, and DESe.

26. A method of fabricating a white-light LED according to claim 21, further including the step of forming an inner passivation layer between the LED chip and the yellow thin-film layer.

27. A method of fabricating a white light LED according to claim 26, wherein forming the inner passivation layer includes forming a SiO₂ layer.

28. A method of fabricating a white light LED according to claim 26, wherein forming the inner passivation layer includes forming a Si_xN_y layer.

29. A method of fabricating a white light LED according to claim 21, further including forming an outer passivation layer over the yellow thin-film layer.

30. A method of fabricating a white light LED according to claim 21, further including bonding a first bonding wire to the first electrical contact and bonding a second bonding wire to the second electrical.

31. A method of fabricating a white light LED according to claim 21, further including sealing the LED chip in a package.

32. A light emitting diode (LED), comprising:

an LED chip having a first electrical contact and a second electrical contact, wherein the LED chip emits light having a first wavelength in response to an applied electrical power; and

a tinted thin-film layer over the LED chip;

wherein the tinted thin-film layer interacts with the first wavelength light to produce a second wavelength.

33. An LED according to claim 32, wherein the tinted thin-film layer is selected from a group consisting of ZnSe, CeO₂, Al₂O₃, and Y₂O₃:

Ce.

34. An LED according to claim 32, further including an inner passivation layer between the tinted thin-film layer and the LED chip.

35. An LED according to claim 32, wherein the first wavelength light is converted to white light.

36. An LED according to claim 32, further comprising an outer passivation layer over the tinted thin-film layer.

37. An Led according to claim 32, further comprising a first bonding wire connected to the first electrical contact and a second bonding wire connected to the second electrical contact.

38. An Led according to claim 32, wherein the LED chip has a lateral topology structure.

39. An Led according to claim 32, wherein the LED chip has a vertical topology structure.