Light emitting device with bonded interface
View Patent ↗In some embodiments of the invention, a transparent substrate AlInGaP device includes an etch stop layer that may be less absorbing than a conventional etch stop layer. In some embodiments of the invention, a transparent substrate AlInGaP device includes a bonded interface that may be configured to give a lower forward voltage than a conventional bonded interface. Reducing the absorption and/or the forward voltage in a device may improve the efficiency of the device.
1. A device comprising:
a first semiconductor structure comprising an AlGaInP light emitting layer disposed between an n-type region and a p-type region;
a second semiconductor structure; and
a direct semiconductor-to-semiconductor bond formed at an interface between the first and second semiconductor structures;
wherein:
the bond connects the first semiconductor structure to the second semiconductor structure;
a first semiconductor layer adjacent to the interface is an InGaP layer between 5,000 and 10,000 Å thick that is doped with Te to a concentration of at least 5×10 18 cm −3 ; and
a second semiconductor layer adjacent to the interface is an InGaP layer less than 250 Å thick and doped with Te.
2. The device of claim 1 , wherein at least one of the first and second semiconductor layers adjacent to the interface is roughened wherein the maximum to minimum excursion of the roughness is greater than 15 nm.
3. The device of claim 1 , wherein at least one of the first and second semiconductor layers adjacent to the interface has a bulk lattice constant different from a bulk lattice constant of GaAs.
4. The device of claim 3 wherein at least one of the first and second semiconductor layers adjacent to the interface with the bulk lattice constant different from a bulk lattice constant of GaAs is one of InGaP and AlGaInP.
5. The device of claim 1 , wherein at least one of the first and second semiconductor layers adjacent to the interface has a graded composition.
6. The device of claim 1 , wherein a band gap of at least one of the first and second semiconductor layers adjacent to the interface is greater than a band gap of the light emitting layer.
7. The device of claim 1 , wherein a band gap of at least one of the first semiconductor layers adjacent to the interface is greater than a band gap of the light emitting layer plus 0.025 eV.
8. The device of claim 1 , wherein the second semiconductor structure comprises a transparent GaP layer at least 10 μm thick.
9. The device of claim 1 , wherein at least one of the first and second semiconductor layers adjacent to the interface is more heavily doped than at least one of the p-type region and the n-type region.
10. A device comprising:
a first semiconductor structure comprising an AlGaInP light emitting layer disposed between an n-type region and a p-type region;
a second semiconductor structure; and
a direct semiconductor-to-semiconductor bond formed at an interface between the first and second semiconductor structures;
wherein:
the bond connects the first semiconductor structure to the second semiconductor structure; and
a first semiconductor layer adjacent to the interface is AlGaInP with a thickness less than 500 Å and doped with Te to a concentration greater than 2×10 18 cm −3 ; and
a second semiconductor layer adjacent to the interface is InGaP with an InP composition between 8% and 16%, with a thickness between 2,000 and 20,000 Å, and doped with Te to a concentration of 8×10 18 cm −3 .
11. The device of claim 10 , wherein at least one of the first and second semiconductor layers adjacent to the interface is roughened wherein the maximum to minimum excursion of the roughness is greater than 15 nm.
12. The device of claim 10 , wherein at least one of the first and second semiconductor layers adjacent to the interface has a bulk lattice constant different from a bulk lattice constant of GaAs.
13. The device of claim 12 wherein at least one of the first and second semiconductor layers adjacent to the interface with the bulk lattice constant different from a bulk lattice constant of GaAs is one of InGaP and AlGaInP.
14. The device of claim 10 , wherein at least one of the first and second semiconductor layers adjacent to the interface has a graded composition.
15. The device of claim 10 , wherein a band gap of at least one of the first and second semiconductor layers adjacent to the interface is greater than a band gap of the light emitting layer.
16. The device of claim 10 , wherein a band gap of at least one of the first semiconductor layers adjacent to the interface is greater than a band gap of the light emitting layer plus 0.025 eV.
17. The device of claim 10 , wherein the second semiconductor structure comprises a transparent GaP layer at least 10 μm thick.
18. The device of claim 10 , wherein at least one of the first and second semiconductor layers adjacent to the interface is more heavily doped than at least one of the p-type region and the n-type region.