Wavelength-converted semiconductor light emitting device
View Patent ↗A material such as a phosphor is optically coupled to a semiconductor structure including a light emitting region disposed between an n-type region and a p-type region, in order to efficiently extract light from the light emitting region into the phosphor. The phosphor may be phosphor grains in direct contact with a surface of the semiconductor structure, or a ceramic phosphor bonded to the semiconductor structure, or to a thin nucleation structure on which the semiconductor structure may be grown. The phosphor is preferably highly absorbent and highly efficient. When the semiconductor structure emits light into such a highly efficient, highly absorbent phosphor, the phosphor may efficiently extract light from the structure, reducing the optical losses present in prior art devices.
1. A method comprising:
providing a structure comprising:
a ceramic body including a phosphor, the phosphor being configured to absorb light of a first peak wavelength and emit light of a second peak wavelength; and
a nucleation structure bonded to a surface of the ceramic body; and
growing on the nucleation structure a semiconductor structure comprising a light emitting region disposed between an n-type region and a p-type region, the light emitting region being configured to emit light of the first peak wavelength;
wherein prior to growing, the nucleation structure has a thickness less that one hundred microns.
2. The method of claim 1 wherein a bond between the ceramic body and the nucleation structure is substantially free of metal or adhesives.
3. The method of claim 1 wherein providing a structure comprises pressing the ceramic body and the nucleation structure together at a temperature greater than 500° C. and a pressure greater than 5 psi.
4. The method of claim 1 wherein the nucleation structure is selected from the group of GaN, AlN, SiC, and Al 2 O 3 .
5. The method of claim 1 wherein providing a structure comprises:
providing a nucleation structure formed on a substrate;
bonding the ceramic body to the nucleation structure; and
after bonding, removing the substrate.
6. The method of claim 1 further comprising:
etching the semiconductor structure to expose portions of both the n-type region and the p-type region; and
forming contacts on each of the n-type region and the p-type region.
7. The method of claim 6 wherein at least one of the contacts is reflective.
8. The method of claim 1 wherein the ceramic body is shaped into a lens.
9. The method of claim 1 wherein a surface of the ceramic body is textured or roughened.
10. The method of claim 1 wherein the ceramic body is transparent.
11. The method of claim 1 wherein the ceramic body is opaque.
12. The method of claim 1 wherein prior to growing, the nucleation structure has a thickness less than ten microns.
13. The method of claim 1 wherein prior to growing, the nucleation structure has a thickness less than one micron.
14. The method of claim 1 wherein the structure further comprises a bonding layer disposed between the nucleation structure and the ceramic body.
15. A method comprising:
providing a ceramic body including a phosphor, the phosphor being configured to absorb light of a first peak wavelength and emit light of a second peak wavelength;
providing a semiconductor structure formed on a growth substrate, the semiconductor structure comprising a light emitting region disposed between an n-type region and a p-type region, the light emitting region being configured to emit light of the first peak wavelength;
bonding the ceramic body to a surface of the semiconductor structure; and
after bonding, removing the growth substrate.
16. The method of claim 15 wherein the p-type region is grown over the growth substrate prior to growing the n-type region.
17. The method of claim 16 further comprising annealing the semiconductor structure after removing the growth substrate.
18. The method of claim 15 wherein the surface of the semiconductor structure bonded to the ceramic body is a surface of the n-type region.
19. The method of claim 15 further comprising providing a bonding layer between the semiconductor structure and the ceramic body.