Forming light-emitting diodes using seed particles
View Patent ↗A seed layer for growing a group III-V semiconductor structure is embedded in a dielectric material on a carrier substrate. After the group III-V semiconductor structure is grown, the dielectric material is removed by wet etch to detach the carrier substrate. The group III-V semiconductor structure includes a thick gallium nitride layer of at least 100 microns or a light-emitting structure.
1. A method of fabricating a light-emitting diode (LED), comprising:
providing a first carrier substrate; depositing a first dielectric adhesion layer;
depositing a layer of seed material, wherein the seed material comprises gallium nitride, silicon carbide, or aluminum nitride;
depositing a second dielectric adhesion layer over and around the layer of seed material;
etching the second dielectric adhesion layer to a thickness less than the average particle size of the seed material;
epitaxially growing a group III-V semiconductor structure;
bonding a second carrier substrate to the group III-V semiconductor structure; and,
wet etching the first and second dielectric adhesion layers to detach the first carrier substrate.
2. The method of claim 1 , further comprising planarizing a bottom surface of the group III-V semiconductor structure.
3. The method of claim 2 , wherein the planarizing a bottom surface comprises dry etching.
4. The method of claim 1 , wherein the epitaxially growing a group III-V semiconductor structure comprises:
growing a first doped layer doped with a first impurity of a first conductivity type;
growing an active layer over the first doped layer; and
growing a second doped layer over the active layer, the second doped layer doped with a second impurity of a second conductivity type opposite the first conductivity type.
5. The method of claim 4 , wherein the bonding a second carrier substrate comprises applying glue between the second carrier substrate and the group III-V semiconductor structure or metal bonding the second carrier substrate and the group III-V semiconductor structure.
6. The method of claim 1 , wherein the seed material comprises fine particles or rods.
7. The method of claim 6 , wherein the fine particles are powder with an average diameter of less than about 10 microns.
8. The method of claim 1 , wherein the seed material comprises a number of small crystals and wherein the etching the second dielectric adhesion layer exposes a surface of a substantial number of the small crystals.
9. The method of claim 8 , wherein an average surface area of the exposed surfaces of the substantial number of the small crystals is greater than about 1 square micron.
10. The method of claim 1 , wherein the seed material covers at least 50% of a top surface of the first dielectric adhesion layer.
11. The method of claim 1 , wherein the seed material is deposited by applying a liquid medium having the seed material mixed therein to the first dielectric adhesion layer and then evaporating the liquid medium.
12. The method of claim 1 , wherein the detached first carrier substrate is reused in a subsequent LED fabricating method as a first carrier substrate.
13. The method of claim 1 , wherein the first carrier substrate is silicon.
14. The method of claim 1 , wherein the wet etching comprising immersing in an etching solution including hydrofluoric acid.
15. A method of fabricating a light-emitting diode (LED), comprising:
providing a carrier substrate;
depositing a first dielectric adhesion layer;
depositing a layer of seed material, wherein the seed material comprises gallium nitride, silicon carbide, or aluminum nitride;
depositing a second dielectric adhesion layer over and around the layer of seed material;
etching the second dielectric adhesion layer to a thickness less than the average particle size of the seed material;
epitaxially growing a gallium nitride layer, wherein a total thickness of the gallium nitride layer is more than about 100 microns; and,
wet etching the first and second dielectric adhesion layers to detach the carrier substrate from the gallium nitride layer.
16. The method of claim 15 , further comprising planarizing a bottom surface of the gallium nitride layer.
17. The method of claim 15 , further comprising growing a light-emitting structure, said light-emitting structure comprises a first doped layer doped with a first impurity of a first conductivity type; an active layer over the first doped layer; and a second doped layer over the active layer, the second doped layer doped with a second impurity of a second conductivity type opposite the first conductivity type.
18. The method of claim 15 , wherein the seed material comprises particles or rods.
19. A method comprising:
depositing a first dielectric adhesion layer over a substrate;
depositing a layer of seed material over the first dielectric adhesion layer, wherein the seed material comprises gallium nitride, silicon carbide, or aluminum nitride;
depositing a second dielectric adhesion layer over the layer of seed material;
etching the second dielectric adhesion layer to expose a portion of the layer of seed material;
forming a group III-V semiconductor structure over the portion of the layer of seed material; and
removing the first and second dielectric adhesion layers to detach the first carrier substrate.
20. The method of claim 19 , wherein removing the first and second dielectric adhesion layers to detach the first carrier substrate includes etching the first and second dielectric adhesion layers to detach the first carrier substrate.