Light emitting diode and fabrication method thereof
A light emitting diode (LED) and a method for fabricating the same, capable of improving brightness by forming a InGaN layer having a low concentration of indium, and whose lattice constant is similar to that of an active layer of the LED, is provided. The LED includes: a buffer layer disposed on a sapphire substrate; a GaN layer disposed on the buffer layer; a doped GaN layer disposed on the GaN layer; a GaN layer having indium disposed on the GaN layer; an active layer disposed on the GaN layer having indium; and a P-type GaN disposed on the active layer. Here, an empirical formula of the GaN layer having indium is given by In(x)Ga(1-x)N and a range of x is given by 0<x<2, and a thickness of the GaN layer having indium is 50-200 Å.
1. A method for fabricating a light emitting diode, comprising:
forming a first conductive type semiconductor layer;
forming at least one GaN layer having indium directly on the first conductive type semiconductor layer;
forming at least one GaN layer directly on the at least one GaN layer having indium;
forming an active layer directly on the at least one GaN layer, wherein the active layer is formed of a multi-quantum well structure having an InGaN layer and a GaN layer; and
forming a second conductive type semiconductor layer on the active layer, wherein the second conductive type semiconductor layer has a thickness of 750-1500 Å.
2. The method according to claim 1 , wherein an empirical formula of the at least one GaN layer having indium is given by In x Ga 1-x N and a range of x is given by 0<x<0.2.
3. The method according to claim 1 , wherein a thickness of the at least one GaN layer is 10-30 Å.
4. The method according to claim 1 , wherein a thickness of the first conductive type semiconductor layer is 1-3 μm.
5. The method according to claim 1 , wherein the active layer includes at least one well layer and at least one barrier layer formed in 1 period to 7 periods.
6. The method according to claim 1 , further comprising:
preparing a substrate;
forming a buffer layer on the substrate; and
forming a first GaN layer on the buffer layer.
7. The method according to claim 6 , wherein the buffer layer is formed of GaN-based material.
8. The method according to claim 6 , wherein a thickness of the first GaN layer is 1-3 μm.
9. The method according to claim 6 , wherein a total thickness of the first GaN layer and the first conductive type semiconductor layer is 2-6 μm.
10. The method according to claim 6 , wherein the first GaN layer includes an undoped GaN layer.
11. The method according to claim 1 , further comprising:
forming a transparent metal on the second conductive type semiconductor layer, wherein the transparent metal is ITO (Indium-Tin-Oxide).
12. The method according to claim 1 , wherein the second conductive type semiconductor layer includes at least one well layer and at least one barrier layer.
13. The method according to claim 1 , wherein the at least one GaN layer having indium has a thickness less than 200 Å.
14. The method according to claim 13 , wherein the at least one GaN layer having indium has a thickness greater than 50 Å and less than 200 Å.
15. A method for fabricating a light emitting diode, comprising:
preparing a substrate;
forming a buffer layer on the substrate;
forming a first GaN layer on the buffer layer;
forming a first conductive type semiconductor layer on the first GaN layer;
forming at least one GaN layer having indium directly on the first conductive type semiconductor layer;
forming at least one second GaN layer directly on the at least one GaN layer having indium;
forming an active layer directly on the at least one second GaN layer, wherein the active layer is formed of a multi-quantum well structure having an InGaN layer and a GaN layer; and
forming a second conductive type semiconductor layer on the active layer,
wherein a total thickness of the first GaN layer and the first conductive type semiconductor layer is 2-6 μm.
16. The method according to claim 15 , wherein a thickness of the at least one second GaN layer is 10-30 Å.
17. The method according to claim 15 , wherein the at least one GaN layer having indium has a thickness less than 200 Å.
18. The method according to claim 17 , wherein the at least one GaN layer having indium has a thickness greater than 50 Å and less than 200 Å.
19. A method for fabricating a light emitting diode, comprising:
forming a first conductive type semiconductor layer;
forming at least one GaN layer having indium directly on the first conductive type semiconductor layer;
forming at least one GaN layer directly on the at least one GaN layer having indium, wherein a thickness of the at least one GaN layer is 10-30 Å;
forming an active layer including InGaN directly on the at least one GaN layer, wherein the active layer includes at least one well layer and at least one barrier layer, and wherein the active layer is formed of a multi-quantum well structure having an InGaN layer and a GaN layer; and
forming a second conductive type semiconductor layer on the active layer, wherein the second conductive type semiconductor layer has a thickness of 750-1500 Å.