Nitride semiconductor LED improved in lighting efficiency and fabrication method thereof

1. A fabrication method of nitride semiconductor Light Emitting Diodes (LEDs), the method comprising the following steps of:

(a) forming an n-doped semiconductor layer on a substrate;

(b) forming an active layer on the n-doped semiconductor layer;

(c) forming a p-doped semiconductor layer on the active layer;

(d) forming a p+-doped semiconductor layer on the p-doped semiconductor layer;

(e) implanting n-dopant ions into the p+-doped semiconductor layer to convert at least a portion of the p+-doped semiconductor layer into an n+-doped semiconductor layer so that the n+-doped semiconductor layer cooperates with a remaining region of the p+-doped semiconductor layer to form a reverse bias tunneling junction; and

(f) mesa-etching a resultant semiconductor structure to the extent of exposing a partial area of the n-doped semiconductor layer.

2. The fabrication method of nitride semiconductor LEDs according to claim 1 , wherein the ion implantation step (e) comprises:

forming a SiO 2 layer on the resultant semiconductor layer;

etching the SiO 2 layer to expose at least a portion of the p+-doped semiconductor layer;

implanting n-dopant ions through the etched portion of the SiO 2 layer; and

removing the SiO 2 layer via heat treatment.

3. The fabrication method of nitride semiconductor LEDs according to claim 1 , wherein the ion implantation step (e) implants n-dopants in high and low energy levels into an upper region of the p+-doped semiconductor layer to form en n+-doped semiconductor layer on the remaining region of the p+-doped semiconductor layer and an upper n-doped semiconductor layer on the n+-doped semiconductor layer, thereby realizing lateral current spreading.

4. The fabrication method of nitride semiconductor LEDs according to claim 1 , wherein the ion implantation step (e) comprises: implanting n-dopant ions at a first energy level into an upper region of the n+-doped semiconductor layer to form an n+-doped semiconductor layer on the remaining region of the p+-doped semiconductor layer; and implanting n-dopant at a second energy level different from the first energy level into the upper region of the n+-doped semiconductor layer to form an upper n-doped semiconductor layer on the n+-doped semiconductor layer, thereby realizing lateral current spreading.

5. The fabrication method of nitride semiconductor LEDs according to claim 4 , further comprising the step of:

(g) forming p- and n-electrodes on the upper n-doped semiconductor layer and the exposed partial area of the n-doped semiconductor layer, respectively, after the ion implantation step (e).

6. The fabrication method of nitride semiconductor LEDs according to claim 3 , further comprising the step of:

(g) forming p- and n-electrodes on the upper n-doped semiconductor layer end the exposed partial area of the n-doped semiconductor layer, respectively, after the ion implantation step (e).

7. The fabrication method of nitride semiconductor LEDs according to claim 1 , further comprising the step of:

(h) forming a p-transparent electrode and an n-electrode on the n+-doped semiconductor layer and the exposed partial area of the n-doped semiconductor layer, respectively, after the etching step (f ),

wherein the transparent electrode is made of at least one selected from a group consisting of Indium-Tin oxide (ITO), Cadmium-Tin Oxide (CTO) and Titanium Tungsten Nitride (TiWN).

8. A fabrication method of nitride semiconductor Light Emitting Diodes (LEDs), the method comprising the following steps of:

(a) forming an n-doped semiconductor layer on a substrate;

(b) forming art active layer on the n-doped semiconductor layer;

(c) forming a p-doped semiconductor layer on the active layer;

(d) forming p+-doped semiconductor layer on the p-doped semiconductor layer;

(e) forming an upper n-doped semiconductor layer on the p+-doped semiconductor layer;

(f) implanting n-dopant ions into the upper n-doped semiconductor layer to convert at least a partial region of the upper n-doped semiconductor layer into an n+-doped semiconductor layer so that the n+-doped semiconductor layer cooperates with a remaining region of the p+-doped semiconductor layer to form a reverse bias tunneling junction; and

(g) mesa-etching a resultant semiconductor structure to the extent of exposing a partial area of the n-doped semiconductor layer.

9. The fabrication method of nitride semiconductor LEDs according to claim 8 , wherein the ion implantation step (f) comprises:

forming a SiO 2 layer on the resultant semiconductor layer;

etching the SiO 2 layer to expose at least a portion of the p+-doped semiconductor layer;

implanting n-dopant ions through the etched portion of the SiO 2 layer; and

removing the SiO 2 layer via heat treatment.

10. The fabrication method of nitride semiconductor LEDs according to claim 8 , wherein the ion implantation step (f) comprises: implanting n+-dopants at a predetermined energy level into a lower region of the n-doped semiconductor layer to form an n+-doped semiconductor layer, whereby the n+-doped semiconductor layer cooperates with en upper remaining region of the n-doped semiconductor layer to realize lateral current spreading.

11. The fabrication method of nitride semiconductor LEDs according to claim 10 , further comprising the step of:

(h) forming p- and n-electrodes on the upper n-doped semiconductor layer and the exposed partial area of the n-doped semiconductor layer, respectively, after the ion implantation step (f).

12. The fabrication method of nitride semiconductor LEDs according to claim 8 , further comprising the step of:

(i) forming a p-transparent and an n-electrode on the n+-doped semiconductor layer and the exposed partial area of the n-doped semiconductor layer, respectively, after the etching step (g),

wherein the transparent electrode is made of at least one selected from a group consisting of Indium-Tin Oxide (ITO), Cadmium-Tin Oxide (CTO) and Titanium Tungsten Nitride (TiWN).