LED structures for reduced non-radiative sidewall recombination
LED structures are disclosed to reduce non-radiative sidewall recombination along sidewalls of vertical LEDs including p-n diode sidewalls that span a top current spreading layer, bottom current spreading layer, and active layer between the top current spreading layer and bottom current spreading layer.
1. A light emitting diode (LED) comprising:
a p-n diode layer including:
a top doped layer doped with a first dopant type;
a bottom doped layer doped with a second dopant type opposite the first dopant type; and
an active layer between the top doped layer and the bottom doped layer; and
p-n diode layer sidewalls spanning the top doped layer, the active layer, and the bottom doped layer; and
a semiconductor passivation layer formed on the p-n diode layer sidewalls spanning the top doped layer, the active layer, and the bottom doped layer, wherein the semiconductor passivation layer spans underneath the bottom doped layer and completely covers a bottom surface of the bottom doped layer.
2. The LED of claim 1 , wherein the semiconductor passivation layer is formed directly on the p-n diode layer sidewalls spanning the top doped layer, the active layer, and the bottom doped layer.
3. The LED of claim 1 , further comprising a conductive contact formed on and underneath the semiconductor passivation layer.
4. The LED of claim 3 , wherein the conductive contact comprises a multiple layer stack.
5. The LED of claim 4 , wherein the multiple layer stack comprises an electrode layer and a diffusion barrier layer.
6. The LED of claim 1 , wherein the semiconductor passivation layer does not reach a top surface of the p-n diode layer.
7. The LED of claim 6 , wherein the semiconductor passivation layer is p-doped, and the top doped layer is n-doped.
8. The LED of claim 1 , wherein the p-n diode layer is designed for emission of red light.
9. The LED of claim 8 , wherein the p-n diode layer is formed of phosphorous based materials.
10. The LED of claim 8 , wherein the semiconductor passivation layer comprises AlInP.
11. The LED of claim 10 , wherein the AlInP is p-doped.
12. The LED of claim 8 , wherein the semiconductor passivation layer comprises GaN.
13. The LED of claim 12 , wherein the GaN is p-doped.
14. A light emitting diode (LED) comprising:
a p-n diode layer including:
a top doped layer doped with a first dopant type;
a bottom doped layer doped with a second dopant type opposite the first dopant type; and
an active layer between the top doped layer and the bottom doped layer; and
p-n diode layer sidewalls spanning the top doped layer, the active layer, and the bottom doped layer; and
a semiconductor passivation layer formed on the p-n diode layer sidewalls spanning the top doped layer, the active layer, and the bottom doped layer, wherein the semiconductor passivation layer is p-doped.
15. The LED of claim 14 , wherein the active layer comprises multiple quantum well layers and multiple quantum barrier layers.
16. The LED of claim 15 , wherein the multiple quantum well layers and multiple quantum barrier layers comprise AlGaInP, and the quantum barrier layers have a higher Al concentration than the quantum well layers.
17. The LED of claim 14 , wherein the semiconductor passivation layer is a III-V semiconductor passivation layer.
18. The LED of claim 17 , wherein the III-V semiconductor passivation layer is formed directly on the p-n diode layer sidewalls spanning the top doped layer, the active layer, and the bottom doped layer.
19. The LED of claim 14 , wherein the p-n diode layer is formed of phosphorous based materials.
20. The LED of claim 14 , further comprising a conductive contact formed on and underneath the semiconductor passivation layer, wherein the semiconductor passivation layer spans underneath the bottom doped layer and completely covers a bottom surface of the bottom doped layer.