Method for fabricating high-efficiency light emitting diode having light emitting window electrode structure
A lateral light emitting diode device includes: a substrate; an n-type GaN layer disposed on the substrate; an activation layer disposed on the n-type GaN layer; a p-type GaN layer disposed on the activation layer; a current spreading layer disposed on the p-type GaN layer; a p-electrode disposed on the current spreading layer; a MESA region formed by removing portions of the current spreading layer, the p-type GaN layer, the activation layer, and the n-type GaN layer; a transparent window layer disposed on the n-type GaN layer in the entire or part of the MESA region; a plurality of contact plugs which is in contact with the n-type GaN layer through the transparent window layer; and an n-electrode disposed on the transparent window layer to connect the plurality of contact plugs to each other.
1. A lateral light emitting diode device comprising:
a substrate;
an n-type GaN layer on the substrate;
an emission region comprising:
an activation layer on the n-type GaN layer,
a p-type GaN layer on and vertically aligned the activation layer, and
a current spreading layer on and vertically aligned with the p-type GaN layer;
a p-electrode on the current spreading layer;
a transparent window layer on the n-type GaN layer in a MESA region of the lateral light emitting diode device;
a plurality of contact plugs in contact with the n-type GaN layer through the transparent window layer; and
an n-electrode on the transparent window layer to connect the plurality of contact plugs to each other,
wherein the n-electrode and the MESA region extend in a first direction, the plurality of contact plugs are arranged in the first direction, and a distance between adjacent ones of the contact plugs sequentially decreases proceeding in the first direction.
2. The lateral light emitting diode device as set forth in claim 1 , wherein:
a top surface of the transparent window layer is higher than the current spreading layer.
3. The lateral light emitting diode device as set forth in claim 1 , further comprising at least one of:
an insulating sidewall on a side surface of the transparent window at the boundary of the MESA region and the emission region; and
a seed layer between the n-type GaN layer and the transparent window layer.
4. The lateral light emitting diode device as set forth in claim 3 , wherein:
the transparent window layer includes at least one selected from the group consisting of zinc oxide (ZnO), zirconium oxide (ZrO 2 ), titanium oxide (TiO 2 ), chromium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium oxide (In 2 O 3 ), tin oxide (SnO 2 ), silicon oxide (SiO 2 ), magnesium fluoride (MgF 2 ), and a combination thereof.
5. The lateral light emitting diode device as set forth in claim 1 , wherein:
the transparent window layer has a multilayer structure having a sequentially reduced refractive index.
6. The lateral light emitting diode device as set forth in claim 1 , wherein:
the MESA region includes a peripheral MESA region covering part of the emission region and an n-electrode MESA region crossing part of the emission region, and
the transparent window layer is only in the n-electrode MESA region.
7. The lateral light emitting diode device as set forth in claim 1 , further comprising:
an insulating sidewall on a side surface of the transparent window at the boundary of the MESA region and the emission region; and
a seed layer between the n-type GaN layer and the transparent window layer.
8. The lateral light emitting diode device as set forth in claim 1 , wherein the transparent window layer comprises a metal oxide.
9. The lateral light emitting diode device as set forth in claim 1 , wherein the transparent window layer comprises a multilayer structure in which each sequential layer has a smaller refractive index.
10. The lateral light emitting diode device as set forth in claim 9 , wherein the multilayer structure comprises ZnO, indium tin oxide (ITO), silicon nitride and/or a silicon oxide.
11. The lateral light emitting diode device as set forth in claim 9 , wherein the multilayer structure comprises, in sequence, ZnO, indium tin oxide (ITO), silicon nitride and a silicon oxide.
12. The lateral light emitting diode device as set forth in claim 1 , wherein the MESA region includes an n-electrode MESA region crossing part of the emission region, and the transparent window layer is in the n-electrode MESA region.
13. The lateral light emitting diode device as set forth in claim 1 , wherein the substrate has a crystal structure and orientation similar to the n-type GaN layer, the activation layer and the p-type GaN layer, and is configured to epitaxially grow the n-type GaN layer, the activation layer, and the p-type GaN layer.
14. The lateral light emitting diode device as set forth in claim 1 , wherein the substrate comprises sapphire, silicon carbide (SiC), aluminum nitride (AlN), aluminum oxide (Al 2 O 3 ), or silicon.
15. The lateral light emitting diode device as set forth in claim 1 , further comprising a buffer layer on the substrate, wherein the buffer layer reduces a difference in a grating constant between the substrate and the n-type GaN layer and/or relieves stress between the substrate and the n-type GaN layer.
16. A lateral light emitting diode device comprising:
a substrate;
an emission region comprising:
an n-type GaN layer on the substrate;
an activation layer on the n-type GaN layer;
a p-type GaN layer on the activation layer;
a current spreading layer on the p-type GaN layer;
a p-electrode on the current spreading layer;
a transparent window layer on the n-type GaN layer in a MESA region of the lateral light emitting diode device, wherein the transparent window layer has a multilayer structure having a sequentially reduced refractive index;
a plurality of contact plugs in contact with the n-type GaN layer through the transparent window layer; and
an n-electrode on the transparent window layer to connect the plurality of contact plugs to each other.
17. The lateral light emitting diode device as set forth in claim 16 , wherein the multilayer structure comprises ZnO, indium tin oxide (ITO), silicon nitride and/or a silicon oxide.
18. The lateral light emitting diode device as set forth in claim 16 , wherein the multilayer structure comprises, in sequence, ZnO, indium tin oxide (ITO), silicon nitride and a silicon oxide.
19. The lateral light emitting diode device as set forth in claim 16 , wherein the transparent window layer has a top surface that is higher than a top surface of the current spreading layer.