Light-emitting-diode chip comprising a sequence of GaN-based epitaxial layers which emit radiation and a method for producing the same
View Patent ↗A light-emitting diode chip comprises a GaN-based, radiation-emitting epitaxial layer sequence, an active region, an n-doped layer and a p-doped layer. The p-doped layer is provided, on its main surface facing away from the active region, with a reflective contact metallization comprising a radioparent contact layer and a reflective layer. Methods for fabricating LED chips of this type by thin-film technology are provided, as are LED components containing such LED chips.
1. A light-emitting diode chip comprising:
a GaN-based, radiation-emitting epitaxial layer sequence comprising an active region, an n-doped layer and a p-doped layer; and
a reflective contact metallization assigned to said p-doped layer, said reflective contact metallization configured to reflect radiation emitted by the radiation-emitting layer sequence and comprising:
a radiation permeable contact layer and a reflective layer,
wherein said radiation permeable contact layer is arranged between said p-doped layer and said reflective layer and has a thickness of 10 nm or more, and said radiation permeable contact layer substantially comprises at least one material from the group of materials including indium tin oxide (ITO) and ZnO; and
wherein said reflective layer covers more than 50% of said radiation permeable contact layer.
2. The light-emitting diode chip as recited in claim 1 , wherein said reflective layer comprises Ag.
3. The light-emitting diode chip as recited in claim 1 , wherein said active region comprises one or more undoped layer(s).
4. The light-emitting diode chip as recited in claim 3 , wherein said undoped layer(s) comprise or consist of InGaN or InGaAlN.
5. The light-emitting diode chip as recited in claim 3 , wherein said active region comprises a double heterostructure, a single quantum well or a multi-quantum well.
6. The light-emitting diode chip as recited in claim 1 , wherein said reflective contact metallization further comprises:
a diffusion barrier layer on a side of the reflective layer facing away from the radiation permeable contact layer, and
an additional metal layer on a side of the diffusion barrier layer facing away from the reflective layer wherein the additional metal layer improves a bondability of the light-emitting diode chip.
7. The light-emitting diode chip as recited in claim 6 , wherein the diffusion barrier layer comprises at least one of the following materials: Ti, Pt, W, TiWN.
8. The light-emitting diode chip as recited in claim 6 , wherein the additional metal layer comprises or consists of Au or Al.
9. The light-emitting diode chip as recited in claim 6 , wherein
the radiation permeable contact layer is in direct contact with the reflective layer,
the diffusion barrier layer is in direct contact with the reflective layer, and
the additional metal layer is in direct contact with the diffusion barrier layer.
10. A light-emitting diode chip comprising:
a GaN-based, radiation-emitting epitaxial layer sequence comprising an active region, an n-doped layer and a p-doped layer; and
a reflective contact metallization assigned to said p-doped layer, said reflective contact metallization configured to reflect radiation emitted by the radiation-emitting layer sequence and said reflective contact metallization further comprises:
a reflective layer;
a radiation permeable contact layer on a side of said reflective layer facing said p-doped layer;
a diffusion barrier layer on a side of said reflective layer facing away from the radiation permeable contact layer; and
an additional metal layer on a side of the diffusion barrier layer facing away from the reflective layer wherein the additional metal layer improves a bondability of the light-emitting diode chip,
wherein said reflective layer covers more than 50% of said radiation permeable contact layer; and
wherein said radiation permeable contact layer substantially comprises at least one material from the group of materials including indium tin oxide (ITO) and ZnO.
11. The light-emitting diode chip as recited in claim 10 , wherein the diffusion barrier layer comprises at least one of the following materials: Ti, Pt, W, TiWN.
12. The light-emitting diode chip as recited in claim 10 , wherein the additional metal layer comprises or consists of Au or Al.
13. The light-emitting diode chip as recited in claim 10 , wherein
the radiation permeable contact layer is in direct contact with the reflective layer,
the diffusion barrier layer is in direct contact with the reflective layer, and
the additional metal layer is in direct contact with the diffusion barrier layer.
14. The light-emitting diode chip as recited in claim 10 , wherein said active region comprises one or more undoped layer(s).
15. The light-emitting diode chip as recited in claim 14 , wherein said undoped layer(s) comprise or consist of InGaN or InGaAlN.
16. The light-emitting diode chip as recited in claim 14 , wherein said active region comprises a double heterostructure, a single quantum well or a multi-quantum well.
17. The light-emitting diode chip as recited in claim 10 , wherein said radiation permeable contact layer has a thickness of 10 nm or more.