Light-emitting diode structure
View Patent ↗A light-emitting diode structure includes an AuSn or AuIn-containing bonding layer over a substrate, a metal layer disposed over the bonding layer, a p-type doped gallium nitride (p-GaN) layer disposed over the metal layer, a n-type doped gallium nitride (n-GaN) layer approximate the p-GaN layer, a multiple quantum well structure disposed between the n-GaN and p-GaN layers, and a conductive contact disposed on the n-GaN layer. The n-GaN layer includes a rough surface with randomly distributed dips. The nano-sized dips have diameters distributed between about 100 nm and about 600 nm, have a dip density ranging from about 107 grains/cm 2 to about 109 grains/cm 2 , and are spaced from each other with an average spacing S, average diameter D, and a ratio S/D that ranges between about 1.1 and about 1.5. The conductive contact is disposed on some of the nano-sized dips of the rough surface.
1. A light-emitting diode (LED) structure, comprising:
a bonding layer disposed over a substrate, wherein the bonding layer contains AuSn or AuIn;
a metal layer disposed over the bonding layer;
a p-type doped gallium nitride (p-GaN) layer disposed over the metal layer;
a n-type doped gallium nitride (n-GaN) layer approximate the p-GaN layer;
a multiple quantum well (MQW) structure disposed between the n-GaN layer and the p-GaN layer; and
a conductive contact disposed on the n-GaN layer;
wherein the n-GaN layer includes a rough surface with randomly distributed nano-sized dips, wherein the nano-sized dips have diameters distributed between about 100 nm and about 600 nm and a dip density ranging from about 10 7 grains/cm 2 to about 10 9 grains/cm 2 , wherein the nano-sized dips are spaced from each other with an average spacing S and an average diameter D, wherein a ratio of S/D ranges between about 1.1 and about 1.5, and wherein the conductive contact is disposed on some of the nano-sized dips of the rough surface.
2. The LED structure of claim 1 , wherein the substrate includes one of a silicon wafer and a metal plate.
3. The LED structure of claim 1 , further comprising a high reflective metal film disposed between the substrate and the p-GaN layer.
4. A light-emitting diode (LED) structure, comprising:
a substrate;
a bonding layer disposed over the substrate, wherein the bonding layer contains AuSn or AuIn;
a metal layer disposed over the bonding layer;
a first doped gallium nitride layer disposed over the metal layer;
a multiple quantum well (MQW) structure disposed over the first doped gallium nitride layer;
a second doped gallium nitride layer disposed over the MQW structure, wherein the second doped gallium nitride layer has a roughened surface that includes a plurality of nano-sized dips, wherein the nano-sized dips have diameters distributed between about 100 nm and about 600 nm and a dip density ranging from about 10 7 grains/cm 2 to about 10 9 grains/cm 2 , wherein the nano-sized dips are spaced from each other with an average spacing S and an average diameter D, wherein a ratio of S/D ranges between about 1.1 and about 1.5; and a metal contact disposed on at least some of the nano-sized dips of the roughened surface.
5. The LED structure of claim 4 , wherein the nano-sized dips are randomly distributed.
6. The LED structure of claim 4 , further comprising one or more trenches that extend at least partially though the first and second doped gallium nitride layers and the MQW structure.
7. The LED structure of claim 4 , further comprising a reflective layer disposed between the substrate and the first doped gallium nitride layer.
8. The LED structure of claim 4 , wherein the substrate includes a silicon wafer or a metal plate.
9. A light-emitting diode (LED) structure, comprising:
a substrate;
a bonding layer disposed over the substrate, wherein the bonding layer contains AuSn or AuIn;
a metal layer disposed over the bonding layer;
a first doped semiconductor layer disposed over the metal layer;
a light-emitting layer disposed over the first doped semiconductor layer;
a second doped semiconductor layer disposed over the light-emitting layer, wherein the first and second doped semiconductor layers have different types of conductivity, and wherein the second doped semiconductor layer includes a rough surface with a plurality of miniature-sized dips, wherein the miniature-sized dips have diameters distributed between about 100 nm and about 600 nm and a dip density ranging from about 10 7 grains/cm 2 to about 10 9 grains/cm 2 , wherein the miniature-sized dips are spaced from each other with an average spacing S and an average diameter D, wherein a ratio of S/D ranges between about 1.1 and about 1.5; and a metal pad disposed on some of the miniature-sized dips of the roughened surface.
10. The LED structure of claim 9 , wherein the miniature-sized dips are randomly distributed.
11. The LED structure of claim 9 , wherein the first and second doped semiconductor layers each include gallium nitride.
12. The LED structure of claim 9 , wherein:
the first doped semiconductor layer is a p-type layer; and
the second doped semiconductor layer is an n-type layer.
13. The LED structure of claim 9 , wherein the substrate includes a silicon wafer or a metal plate.