Light-emitting diode with current-spreading region

• US 8,823,049 B2
• Filed: 03/11/2013
• Issued: 09/02/2014
• Est. Priority Date: 08/18/2008
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: TSMC Solid State Lighting Ltd. (Ennostar, Inc.)
• Inventors: Chen, Ding-Yuan, Yu, Chen-Hua, Chiou, Wen-Chih
• Primary Examiner(s): TRAN, MINH LOAN
• Application Number:
  US13/793,198
• Publication Number:
  US 20130264539A1
• Time in Patent Office: 540 Days
• Field of Search: 257/102, 257/103, 257/E33.011
• US Class Current: 257/102
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/0066 with a substrate not being a III-V compound
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/36 characterised by the electrodes
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

A light-emitting diode (LED) device is provided. The LED device has a lower LED layer and an upper LED layer with a light-emitting layer interposed therebetween. A current blocking layer is formed in the upper LED layer such that current passing between an electrode contacting the upper LED layer flows around the current blocking layer. When the current blocking layer is positioned between the electrode and the light-emitting layer, the light emitted by the light-emitting layer is not blocked by the electrode and the light efficiency is increased. The current blocking layer may be formed by converting a portion of the upper LED layer into a resistive region. In an embodiment, ions such as magnesium, carbon, or silicon are implanted into the upper LED layer to form the current blocking layer.

Claims

1. A light-emitting diode (LED) device comprising:

a substrate;

an LED structure formed on the substrate, the LED structure including an upper layer and a lower layer with a light-emitting layer positioned between the upper layer and the lower layer; and

a current blocking layer formed in the upper layer, wherein the current blocking layer comprises a region of resistive material comprising implanted impurities;

wherein;

the upper layer includes a first layer and a second layer;

the current blocking layer is formed in the first layer; and

the second layer and the light-emitting layer are disposed on opposite sides of the first layer.

2. The LED device of claim 1, wherein the implanted impurities comprise magnesium, carbon, or silicon ions implanted or diffused into the upper layer.

3. The LED device of claim 1, further comprising a first electrode and a second electrode positioned on a first side of the substrate, the first electrode contacting the upper layer and the second electrode contacting the lower layer.

4. The LED device of claim 3, wherein the first electrode is positioned above the current blocking layer.

5. The LED device of claim 1, wherein the current blocking layer has a width of about 50 Å

to about 500 μ

m.

6. A photonic lighting device, comprising:

a substrate;

a first layer disposed over the substrate, the first layer containing a first group III-V compound having a first type of conductivity;

an active layer disposed over the first layer;

a second layer disposed over the active layer, the second layer containing a second group III-V compound having a second type of conductivity different from the first type, wherein the second layer has a same material composition throughout;

a current blocking layer disposed in the second layer; and

an electrode disposed over, and electrically coupled to, the second layer, the electrode being aligned with the currently blocking layer.

7. The photonic lighting device of claim 6, further comprising a further electrode disposed over, and electrically coupled to, the first layer.

8. The photonic lighting device of claim 6, wherein the current blocking layer includes a resistive region.

9. The photonic lighting device of claim 8, wherein the resistive region contains implanted impurities.

10. The photonic lighting device of claim 9, wherein the implanted impurities include at least one of:

silicon, carbon, or magnesium ions.

11. The photonic lighting device of claim 6, wherein the current blocking layer has a width in a range from about 50 angstroms to about 500 microns.

12. The photonic lighting device of claim 6, wherein:

the first group III-V compound includes n-doped gallium nitride;

the second group III-V compound includes p-doped gallium nitride; and

the active layer includes a multiple quantum well.

13. The photonic lighting device of claim 6, wherein the electrode contains at least one of:

titanium, aluminum, gold, nickel, or alloys thereof.

14. The photonic lighting device of claim 6, wherein the substrate contains one of:

sapphire, silicon, or silicon carbide.

15. A light-emitting diode, comprising:

a substrate;

a first semiconductor layer located over the substrate, the first semiconductor layer containing an n-doped group III-V compound;

a multiple quantum well located over the first semiconductor layer;

a second semiconductor layer located over the multiple quantum well, the second semiconductor layer containing a p-doped III-V compound having a uniform material composition throughout;

a resistive current blocking element located in the second semiconductor layer;

a first electrode located over, and electrically coupled to, the first semiconductor layer;

a second electrode located over, and electrically coupled to, the second semiconductor layer, the second electrode being vertically aligned with the currently blocking element.

16. The light-emitting diode of claim 15, wherein the current blocking element contains implanted impurities.

17. The light-emitting diode of claim 16, wherein the implanted impurities include at least one of:

silicon, carbon, or magnesium ions.

18. The light-emitting diode of claim 15, wherein the current blocking element has a width in a range from about 50 angstroms to about 500 microns.

19. The light-emitting diode of claim 15, wherein:

the substrate contains one of;

sapphire, silicon, or silicon carbide;

the n-doped III-V compound includes n-doped gallium nitride;

the p-doped group III-V compound includes p-doped gallium nitride; and

the first and second electrodes each contain at least one of;

titanium, aluminum, gold, nickel, or alloys thereof.