Substrate structure removal
Fabrication of a heterostructure, such as a group III nitride heterostructure, for use in an optoelectronic device is described. The heterostructure can be epitaxially grown on a sacrificial layer, which is located on a substrate structure. The sacrificial layer can be at least partially decomposed using a laser. The substrate structure can be completely removed from the heterostructure or remain attached thereto. One or more additional solutions for detaching the substrate structure from the heterostructure can be utilized. The heterostructure can undergo additional processing to form the optoelectronic device.
1. A method of fabricating a group III nitride heterostructure, the method comprising:
epitaxially growing a sacrificial layer over a substrate structure, wherein the substrate structure includes a substrate and a set of group III nitride layers directly on the substrate, wherein the sacrificial layer is grown directly on a surface of a group III nitride layer in the set of group III nitride layers;
epitaxially growing the group III nitride heterostructure directly on the sacrificial layer;
decomposing the sacrificial layer by irradiating the sacrificial layer with a laser; and
etching the sacrificial layer with hydrofluoric acid, wherein the etching and the decomposing fully release the group III nitride heterostructure from the substrate structure.
2. The method of claim 1 , further comprising bonding a handling member to a top surface of the group III nitride heterostructure prior to the decomposing.
3. The method of claim 2 , wherein the bonding includes soldering the handling member to the top surface of the group III nitride heterostructure.
4. The method of claim 1 , wherein the top surface of the group III nitride heterostructure is a surface of a p-type layer, and wherein the method further comprises attaching a submount including a set of electrodes to the p-type layer.
5. The method of claim 4 , wherein a thermal conductivity magnitude of the submount is at least a thermal conductivity magnitude of the p-type layer.
6. The method of claim 4 , wherein the submount is formed of silicon carbide.
7. The method of claim 1 , wherein a first group III nitride layer in the group III nitride heterostructure immediately adjacent to the sacrificial layer includes n-type doping, and wherein the method further includes forming an n-type electrode on a surface of the first group III nitride layer after the decomposing.
8. The method of claim 1 , wherein the sacrificial layer has a smaller bandgap than a bandgap of each layer in the substrate structure.
9. The method of claim 1 , further comprising patterning a surface of the substrate structure prior to growing the sacrificial layer directly on the surface.
10. The method of claim 1 , wherein radiation generated by the laser varies in a lateral plane of the sacrificial layer.
11. The method of claim 1 , further comprising forming a covering layer on a bottom layer of the group III nitride heterostructure after the decomposing.
12. The method of claim 11 , wherein the covering layer is formed of an insulating transparent material.
13. A method of fabricating an optoelectronic device, the method comprising:
epitaxially growing a sacrificial layer over a substrate structure;
epitaxially growing a group III nitride heterostructure directly on the sacrificial layer, wherein the group III nitride heterostructure includes an active region for the optoelectronic device, wherein a first group III nitride layer in the group III nitride heterostructure immediately adjacent to the sacrificial layer includes n-type doping;
decomposing the sacrificial layer by irradiating the sacrificial layer with a laser to at least partially release the group III nitride heterostructure from the substrate structure, wherein radiation generated by the laser varies in a lateral plane of the sacrificial layer; and
forming an n-type electrode on a surface of the first group III nitride layer after the decomposing.
14. The method of claim 13 , wherein the substrate structure includes a substrate and a set of group III nitride layers directly on the substrate, wherein the sacrificial layer is grown directly on a surface of a group III nitride layer in the set of group III nitride layers.
15. The method of claim 13 , further comprising attaching a p-type electrode to a p-type contact layer of the group III nitride heterostructure.
16. The method of claim 15 , further comprising attaching a submount to at least one of the n-type electrode or the p-type electrode.
17. The method of claim 13 , wherein the decomposing further includes applying a mechanical force to the group III nitride heterostructure.
18. A method of fabricating an optoelectronic device, the method comprising:
epitaxially growing a sacrificial layer over a substrate structure;
epitaxially growing a group III nitride heterostructure directly on the sacrificial layer, wherein the group III nitride heterostructure includes an active region for the optoelectronic device; and
at least partially decomposing the sacrificial layer by irradiating the sacrificial layer with a laser to at least partially release the group III nitride heterostructure from the substrate structure, wherein radiation generated by the laser varies in a lateral plane of the sacrificial layer.
19. The method of claim 18 , wherein the irradiating forms a distributed element for manipulating properties of radiation emitted by the active region of the optoelectronic device.
20. The method of claim 18 , further comprising removing the group III nitride heterostructure from the substrate structure using at least one of: a mechanical force, chemical etching, or an electrical current.