LED epitaxial structure

• US 9,147,799 B2
• Filed: 02/26/2014
• Issued: 09/29/2015
• Est. Priority Date: 02/18/2011
• Status: Expired due to Fees

• Current Assignee: Scienbizip Consulting (Shenzhen) Co., Ltd.
• Original Assignee: ShenZhen Treasure City Technology Co., Ltd.
• Inventors: Huang, Shih-Cheng, Tu, Po-Min
• Primary Examiner(s): Matthews, Colleen A
• Assistant Examiner(s): SNOW, COLLEEN ERIN
• Application Number:
  US14/191,376
• Publication Number:
  US 20140175506A1
• Time in Patent Office: 580 Days
• Field of Search: 257/101, 257/E33.007, 438/29, 438/37, 438/45
• US Class Current: 1/1
• 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. The first n-type epitaxial layer has a doping concentration which varies along a thickness direction of the first n-type epitaxial layer.

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, the first n-type epitaxial layer has a plurality of irregular holes therein, and the first n-type epitaxial layer has a doping concentration which varies along a thickness direction of the first n-type epitaxial layer.

2. The LED epitaxial structure of claim 1, wherein the substrate 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. The LED epitaxial structure of claim 1, wherein the first n-type epitaxial layer has 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.

7. The LED epitaxial structure of claim 6, wherein the doping concentration gradually decreases from 10¹⁹ to 10¹⁸.