Method of forming a composite substrate
In a method according to embodiments of the invention, a III-nitride layer is grown on a growth substrate. The III-nitride layer is connected to a host substrate. The growth substrate is removed. The growth substrate is a non-III-nitride material. The growth substrate has an in-plane lattice constant a substrate . The III-nitride layer has a bulk lattice constant a layer . In some embodiments, [(|a substrate −a layer |)/a substrate ]*100% is no more than 1%.
1. A method comprising:
growing a III-nitride layer with a bulk lattice constant a layer on a non-III-nitride growth substrate with an in-plane lattice constant a substrate such that [(|a substrate −a layer |)/a substrate ]*100% is no more than 1%;
providing a composite substrate comprising the III-nitride layer bonded to a host substrate; and
growing a semiconductor structure comprising a light emitting layer disposed between an n-type region and a p-type region on the III-nitride layer of the composite substrate.
2. The method of claim 1 wherein growing a III-nitride layer comprises growing the III-nitride layer such that a group V face of the III-nitride layer is the growth surface and a group III face of the III-nitride layer is disposed on the non-III-nitride growth substrate.
3. The method of claim 2 wherein growing a semiconductor structure comprises growing the semiconductor structure on the group III face of the III-nitride layer.
4. The method of claim 1 wherein the non-III-nitride growth substrate is ScAlMgO 4 and the III-nitride layer is InGaN.
5. The method of claim 1 wherein the non-III-nitride growth substrate is RAO 3 (MO) n , where R is selected from Sc, In, Y, and the lanthanides; A is selected from Fe (III), Ga, and Al; M is selected from Mg, Mn, Fe (II), Co, Cu, Zn and Cd; and n is an integer ≥1.
6. The method of claim 1 wherein the III-nitride layer is one of InGaN and AlInGaN.
7. The method of claim 1 wherein the III-nitride layer is In x Ga 1-x N, where 0.06≤x≤0.48.
8. The method of claim 1 wherein the composite substrate comprises a non-III-nitride bonding layer disposed between the III-nitride layer and the host substrate.
9. The method of claim 8 wherein the III-nitride layer is InGaN, the bonding layer is SiO x , and the host substrate is sapphire.
10. The method of claim 1 further comprising removing a portion of the composite substrate after growing a semiconductor structure.
11. The method of claim 1 further comprising forming a metal n-contact on the n-type region and a metal p-contact on the p-type region, the metal n- and p-contacts formed on a surface of the semiconductor structure opposite the composite substrate.
12. The method of claim 1 further comprising forming a metal n-contact on the n-type region and a metal p-contact on the p-type region, the metal n- and p-contacts formed on opposite surfaces of the semiconductor structure.
13. The method of claim 1 wherein growing a III-nitride layer comprises forming a zone of weakness in the growth substrate or at an interface between the growth substrate and the III-nitride layer.
14. The method of claim 13 wherein the zone of weakness comprises a region implanted with one of H atoms and N atoms.
15. The method of claim 13 wherein the zone of weakness comprises a plurality of micron scale crystal defects or voids created by irradiation with focused laser beams.
16. The method of claim 1 further comprising positioning a wavelength converting material in a path of light emitted by the light emitting layer.
17. The method of claim 15 wherein the wavelength converting material comprises quantum dots.
18. The method of claim 1 further comprising treating the non-III-nitride growth substrate.
19. The method of claim 1 wherein the non-III-nitride growth substrate is ZnO.