Light emitting devices for light conversion and methods and semiconductor chips for fabricating the same
View Patent ↗Broad spectrum light emitting devices and methods and semiconductor chips for fabricating such devices include a light emitting element, such as a diode or laser, which emits light in a predefined range of frequencies. The light emitting element includes a shaped substrate suitable for light extraction through the substrate and a cavity in the substrate proximate the light emitting element. For example, a trench adjacent at least a portion of the periphery of the light emitting element may be provided. The cavity/trench is configured to contain light conversion material such that light extracted from sidewalls of the cavity/trench passes through the light conversion material contained in the cavity/trench. Methods of fabricating such devices and/or chips are also provided.
1. A light emitting device, comprising:
a substrate;
a semiconductor light emitting element on a surface of the substrate; and
a trench in the substrate adjacent at least a portion of the periphery of the light emitting elements, the trench having at least two sidewalls configured to contain a light conversion material and extending into the substrate to a depth different than a depth of the surface of the substrate on which the semiconductor light emitting element is provided.
2. The light emitting device of claim 1 , wherein at least one of the at least two sidewalls is configured to provide light extraction from the substrate.
3. The light emitting device of claim 2 , wherein at least one of the at least two sidewalls is configured to reflect light into the trench.
4. The light emitting device of claim 1 , wherein the trench has an opening on a surface of the substrate opposite the light emitting element.
5. The light emitting device of claim 1 , wherein the trench has an opening on a same surface of the substrate as the light emitting element.
6. The light emitting device of claim 1 , wherein the trench completely surrounds the light emitting element.
7. The light emitting device of claim 1 , wherein the trench partially surrounds the light emitting element.
8. The light emitting device of claim 1 , further comprising a light conversion material within the trench.
9. The light emitting device of claim 8 , wherein the light conversion material broadens a spectrum of light output by the light emitting element and wherein the light emitting device is a broad spectrum light emitting device.
10. The light emitting device of claim 8 , wherein the light conversion material shifts a spectrum of light output by the light emitting element without substantially broadening the spectrum of light.
11. The light emitting device of claim 9 , wherein an exposed surface of the light conversion material provides a convex surface with respect to the surface of the substrate.
12. The light emitting device of claim 9 , wherein an exposed surface of the light conversion material provides a concave surface with respect to the surface of the substrate.
13. The light emitting device of claim 8 , wherein the light conversion material extends from the trench onto the substrate.
14. The light emitting device of claim 13 , wherein the light conversion material covers a portion of the substrate circumscribed by the trench.
15. The light emitting device of claim 14 , wherein the light conversion material provides a convex surface with respect to a surface of the portion of the substrate covered by the light conversion material.
16. The light emitting device of claim 1 , wherein the light emitting element comprises a gallium nitride based light emitting element.
17. The light emitting device of claim 1 , further comprising a light conversion material in the trench and wherein the light conversion material comprises a luminous material.
18. The light emitting device of claim 17 , wherein the luminous material comprises YAG:Ce, doped YAG:Ce and/or a semiconductor nanocrystal.
19. The light emitting device of claim 17 , wherein the trench is configured to provide an amount of luminous material at a location of the substrate that is proportional to an amount of light output by the location of the substrate.
20. The light emitting device of claim 17 , wherein the composition of the luminous material is substantially uniform within the trench.
21. The light emitting device of claim 17 , wherein the composition of the luminous material is non-uniform within the trench.
22. The light emitting device of claim 1 further comprising a reflective material on an outer one of the at least one sidewalls of the trench.
23. The light emitting device of claim 1 , wherein a substrate sidewall extends through the substrate adjacent and spaced apart from the trench and opposite the trench from the semiconductor light emitting element so as to define a periphery of the light emitting device.
24. The light emitting device of claim 23 , further comprising a reflective material on the substrate sidewall.
25. A light emitting device, comprising:
a substrate;
a semiconductor light emitting element on the substrate;
a trench in the substrate adjacent at least a portion of the periphery of the light emitting element and having at least two sidewalls configured to contain a light conversion material; and
wherein the trench further comprises a floor and wherein the at least two sidewalls comprise tapered sidewalls that extend from the floor of the trench to a surface of the substrate opposite the light emitting element.
26. A light emitting device, comprising:
a substrate;
a semiconductor light emitting element on the substrate;
a trench in the substrate adjacent at least a portion of the periphery of the light emitting element and having at least two sidewalls configured to contain a light conversion material; and
wherein the trench further comprises a floor and wherein the at least two sidewalls comprise a tapered portion that extends from the floor of the trench and a non-tapered portion that extends from the tapered portion of the sidewalls to a surface of the substrate opposite the light emitting element.
27. A light emitting device, comprising:
a substrate;
a semiconductor light emitting element on the substrate;
a trench in the substrate adjacent at least a portion of the periphery of the light emitting element and having at least two sidewalls configured to contain a light conversion material; and
wherein the at least two sidewall comprise a tapered sidewall and a non-tapered sidewall.
28. A light emitting device, comprising:
a substrate;
a semiconductor light emitting element on the substrate;
a trench in the substrate adjacent at least a portion of the periphery of the light emitting element and having at least two sidewalls configured to contain a light conversion material; and
first and second contacts to the light emitting element.
29. The light emitting device of claim 28 , wherein the first contact and the second contact are each on a same surface of the substrate.
30. The light emitting device of claim 28 , wherein the first contact and the second contact are each on opposite surfaces of the substrate.
31. The light emitting device of claim 28 , further comprising a reflector associated with at least one of the first contact and the second contact to the light emitting element.
32. A light emitting device, comprising:
a substrate;
a semiconductor light emitting element on the substrate;
a trench in the substrate adjacent at least a portion of the periphery of the light emitting element and having at least two sidewalls configured to contain a light conversion material; and
a light conversion material within the trench, wherein the light conversion material substantially fills the trench.
33. A light emitting device, comprising:
a substrate;
a semiconductor light emitting element on the substrate;
a trench in the substrate adjacent at least a portion of the periphery of the light emitting element and having at least two sidewalls configured to contain a light conversion material; and
a light conversion material within the trench, wherein the light conversion material includes a light diffusion material.
34. A light emitting device, comprising:
a substrate;
a semiconductor light emitting element on the substrate; and
a trench in the substrate adjacent at least a portion of the periphery of the light emitting element and having at least two sidewalls configured to contain a light conversion material; and
wherein the substrate comprises a silicon carbide substrate.
35. A light emitting device, comprising:
a substrate;
a light emitting element on the substrate; and
at least one cavity in the substrate proximate the light emitting element, the cavity being configured to contain a light conversion material and extending into the substrate to a depth different than a depth of a surface of the substrate on which the semiconductor light emitting element is provided.
36. The light emitting device of claim 35 , further comprising light conversion material within the cavity.
37. The light emitting device of claim 35 , wherein the light emitting element comprises a gallium nitride based light emitting element.
38. The light emitting device of claim 35 , wherein the at least one cavity comprises a trench in the substrate.
39. The light emitting device of claim 35 , wherein the at least one cavity comprises a plurality of cavities in the substrate.
40. The light emitting device of claim 35 , further comprising a protective structure encapsulating the substrate and the light emitting element.
41. A light emitting device, comprising:
a substrate;
a light emitting element on the substrate;
at least one cavity in the substrate proximate the light emitting element, the cavity being configured to contain a light conversion material; and
wherein the substrate comprises a silicon carbide substrate.
42. A light emitting device, comprising:
a substrate;
a light emitting element on the substrate;
at least one cavity in the substrate proximate the light emitting element, the cavity being configured to contain a light conversion material; and
wherein the at least one cavity comprises a frusto-conical opening in the substrate.
43. A method of fabricating a light emitting device having a substrate and a light emitting element on the substrate, comprising:
forming at least one cavity in the substrate proximate the light emitting element, the cavity being configured to contain a light conversion material and extending into the substrate to a depth different than a depth of a surface of the substrate on which the light emitting element is provided.
44. The method of claim 43 , further comprising depositing light conversion material within the cavity.
45. The method of claim 43 , wherein the light emitting element comprises a gallium nitride based light emitting element.
46. The method of claim 43 , wherein forming at least one cavity comprises forming a trench in the substrate.
47. The method of claim 43 , wherein forming at least one cavity comprises forming a frusto-conical opening in the substrate.
48. The method of claim 43 , wherein forming at least one cavity comprises forming a plurality of cavities in the substrate.
49. The method of claim 43 , further comprising encapsulating the substrate and the light emitting element in a protective structure.
50. The method of claim 43 , further comprising mounting the substrate and the light emitting element in a chip-on-board configuration.
51. A method of fabricating a light emitting device having a substrate and a light emitting element on the substrate, comprising:
forming at least one cavity in the substrate proximate the light emitting element, the cavity being configured to contain a light conversion material, wherein the substrate comprises a silicon carbide substrate.