LIGHT EMITTING DIODE ARRAY AND METHOD FOR MANUFACTURING THE SAME

• US 20120292633A1
• Filed: 12/09/2011
• Published: 11/22/2012
• Est. Priority Date: 05/18/2011
• Status: Active Grant

• Current Assignee: Advanced Optoelectronic Technology, Inc.
• Original Assignee: Advanced Optoelectronic Technology, Inc.
• Inventors: HUNG, TZU-CHIEN, SHEN, CHIA-HUI
• Granted Patent: US 8,759,121 B2
• Time in Patent Office: Days
• US Class Current: 257/76
• CPC Class Codes: H01L 27/153 in a repetitive configuration, e.g. LED bars
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• 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

An LED array includes a substrate and a plurality of LEDs formed on the substrate. The LEDs are electrically connected with each other. Each of the LEDs includes a connecting layer, an n-type GaN layer, an active layer, and a p-type GaN layer formed on the substrate in sequence. The connecting layer is etchable by alkaline solution. A bottom surface of the n-type GaN layer which connects the connecting layer has a roughened exposed portion. The bottom surface of the n-type GaN layer has an N-face polarity. A method for manufacturing the LED array is also provided.

Claims

1. An LED array comprising:

a substrate; and

a plurality of LEDs formed on the substrate, the LEDs being electrically connected with each other, each of the LEDs comprising a connecting layer, an n-type GaN layer, an active layer, and a p-type GaN layer formed on the substrate in sequence, a bottom surface of the n-type GaN layer which connects the connecting layer having a roughened exposed portion, the bottom surface of the n-type GaN layer having an N-face polarity.

2. The LED array as claimed in claim 1, wherein a second GaN layer is formed between the connecting layer and the substrate, and a surface of the second GaN layer away from the substrate has a Ga-face polarity.

3. The LED array as claimed in claim 1, wherein the connecting layer is made of a material selected from a group consisting of AlN, SiO₂, and silicon nitride.

4. The LED array as claimed in claim 1, wherein a thickness of the connecting layer is in a range of 5 nm to 1000 nm.

5. The LED array as claimed in claim 1, wherein grooves are formed between the LEDs to separate the LEDs from each other, insulating layers are formed in the grooves, wires are formed on the insulating layers, and the LEDs are electrically connected with each other by the wires.

6. The LED array as claimed in claim 1, wherein The n-type GaN layer has a top surface away from the connecting layer, the top surface comprises a first area and a second area, the active layer, and the p-type GaN layer are formed on the first area in sequence, a p-type electrode is formed on the p-type GaN layer, and an n-type electrode is formed on the second area.

7. The LED as claimed in claim 6, wherein a transparent conductive layer is disposed between the p-type electrode and the p-type GaN layer.

8. A method for manufacturing an LED array comprising:

providing a substrate;

forming a connecting layer, an n-type GaN layer, an active layer and a p-type GaN layer on the substrate in sequence, the connecting layer, the n-type GaN layer, the active layer and the p-type GaN layer cooperatively forming a semiconductor structure, a bottom surface of the second n-type GaN layer facing towards and in connection with the connecting layer having an N-face polarity;

forming grooves in the semiconductor structure and dividing the semiconductor structure into a plurality of LEDs, the grooves at least passing through the p-type GaN layer, the active layer and the n-type GaN layer to expose the connecting layer;

etching the connecting layer by alkaline solution to expose a portion of the bottom surface of the n-type GaN layer, and correspondingly roughening the exposed portion of the bottom surface of the n-type GaN layer during the etching; and

forming electrical connections between the LEDs.

9. The method as claimed in claim 8, wherein the grooves pass through the connecting layer.

10. The method as claimed in claim 8, wherein the alkaline solution is a strong alkaline solution, and the connecting layer and the n-type GaN layer are etched by the strong alkaline solution under a temperature of 85 degrees centigrade for 30 to 60 minutes.

11. The method as claimed in claim 10, wherein the strong alkaline solution is KOH solution or NaOH solution.

12. The method as claimed in claim 8, wherein insulating layers are formed in the grooves before forming electrical connections between the LEDs.

13. The method as claimed in claim 8, wherein the connecting layer is made of a material selected from a group consisting of AlN, SiO₂, and silicon nitride.