LED EPITAXIAL STRUCTURE AND MANUFACTURING METHOD

• US 20120211771A1
• Filed: 11/20/2011
• Published: 08/23/2012
• Est. Priority Date: 02/18/2011
• Status: Active Grant

• Current Assignee: Advanced Optoelectronic Technology, Inc.
• Original Assignee: Advanced Optoelectronic Technology, Inc.
• Inventors: TU, PO-MIN, HUANG, SHIH-CHENG
• Granted Patent: US 8,697,465 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/02513 Microstructure
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer

Abstract

An LED epitaxial structure includes a substrate, a buffer layer and an epitaxial layer. The buffer layer is grown on a top surface of the substrate, and the epitaxial layer is formed on a surface of the buffer layer. The epitaxial layer has a first n-type epitaxial layer and a second n-type epitaxial layer. The first n-type epitaxial layer is formed between the buffer layer and the second n-type epitaxial layer. The first n-type epitaxial layer has a plurality of irregular holes therein.

Claims

1. An LED epitaxial structure, comprising:

a substrate, a buffer layer, and an epitaxial layer, the buffer layer grown on a top surface of the substrate, and the epitaxial layer grown on a top surface of the buffer layer, wherein the epitaxial layer includes a first n-type epitaxial layer, and a second n-type epitaxial layer, the first n-type epitaxial layer is formed between the buffer layer and the second n-type epitaxial layer, and the first n-type epitaxial layer has a plurality of irregular holes therein.

2. The LED epitaxial structure of claim 1, wherein the substrate 12 is a sapphire.

3. The LED epitaxial structure of claim 1, wherein an active layer, and a p-type epitaxial layer are grown sequentially on the second n-type epitaxial layer.

4. The LED epitaxial structure of claim 1, wherein the irregular holes have different sizes, different shapes, and different distribution locations.

5. The LED epitaxial structure of claim 4, wherein a size of the irregular holes near the buffer layer exceeds the size of the irregular holes near the second n-type epitaxial layer.

6. A method for manufacturing an LED epitaxial structure, includes steps:

providing a substrate;

providing a buffer layer grown on a top surface of the substrate;

a first n-type epitaxial layer being grown with doping on a top surface of the buffer layer;

immerging the first n-type epitaxial layer to form a plurality of irregular holes with wet etching;

and a second n-type epitaxial layer, and an active layer, and a p-type epitaxial layer being grown sequentially on the first n-type epitaxial layer.

7. The method for manufacturing the LED epitaxial structure of claim 6, wherein the first n-type epitaxial layer is doped and grown on the top surface of the buffer layer, and the highly doped concentration gradually decreases to the low doped concentration from a bottom surface to a top surface of the first n-type epitaxial layer.

8. The method for manufacturing the LED epitaxial structure of claim 7, wherein the highly doped concentration gradually decreases to the low doped concentration, and the highly doped concentration is near the buffer layer.

9. The method for manufacturing the LED epitaxial structure of claim 6, wherein the first n-type epitaxial layer deposited on the buffer layer of substrate is immerged into an oxalic acid solution.

10. The method for manufacturing the LED epitaxial structure of claim 9, wherein the wet etching is a bias-assisted wet etching, the oxalic acid solution is applied bias, and an electric field is produced.