LED epitaxial structure and manufacturing method

• US 8,697,465 B2
• Filed: 11/20/2011
• Issued: 04/15/2014
• Est. Priority Date: 02/18/2011
• Status: Expired due to Fees

• Current Assignee: Advanced Optoelectronic Technology, Inc.
• Original Assignee: Advanced Optoelectronic Technology, Inc.
• Inventors: TU, PO-MIN, Huang, Shih-Cheng
• Primary Examiner(s): Matthews, Colleen
• Assistant Examiner(s): SNOW, COLLEEN ERIN
• Application Number:
  US13/300,617
• Publication Number:
  US 20120211771A1
• Time in Patent Office: 877 Days
• Field of Search: 257/79, 257/101, 257/E33.007, 438/29, 438/37, 438/45
• US Class Current: 438/37
• 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. 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 doped and grown on a top surface of the buffer layer, the first n-type epitaxial layer being doped and grown with a high doping concentration gradually decreasing to a low doping concentration from a bottom surface to a top surface of the first n-type epitaxial 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.

2. The method for manufacturing the LED epitaxial structure of claim 1, wherein the highly doped concentration gradually decreases to the low doped concentration, and the highly doped concentration is near the buffer layer.

3. The method for manufacturing the LED epitaxial structure of claim 1, wherein the first n-type epitaxial layer deposited on the buffer layer of substrate is immerged into an oxalic acid solution.

4. The method for manufacturing the LED epitaxial structure of claim 3, wherein the wet etching is a bias-assisted wet etching, the oxalic acid solution is applied bias, and an electric field is produced.

5. The method for manufacturing the LED epitaxial structure of claim 1, wherein the highly doped concentration is 10¹⁹ and the low doped concentration is 10¹⁸.