Yi Y Fu

US Patent:

20130032836, Feb 7, 2013

Filed:

Aug 2, 2011

Appl. No.:

13/196828

Inventors:

Zhen Chen - Pleasanton CA, US
Yi Fu - Hacienda Heights CA, US

Assignee:

Bridgelux, Inc. - Livermore CA

International Classification:

H01L 33/32
H01L 33/58

US Classification:

257 95, 438 29, 257 94, 257E33074, 257E33025

Abstract:

A vertical GaN-based blue LED has an n-type layer comprising multiple conductive intervening layers. The n-type layer contains a plurality of periods. Each period of the n-type layer includes a gallium-nitride (GaN) sublayer and a thin conductive aluminum-gallium-nitride (AlGaN:Si) intervening sublayer. In one example, each GaN sublayer has a thickness substantially more than 100 nm and less than 1000 nm, and each AlGaN:Si intervening sublayer has a thickness less than 25 nm. The entire n-type layer is at least 2000 nm thick. The AlGaN:Si intervening layer provides compressive strain to the GaN sublayer thereby preventing cracking. After the epitaxial layers of the LED are formed, a conductive carrier is wafer bonded to the structure. The silicon substrate is then removed. Electrodes are added and the structure is singulated to form a finished LED device. Because the AlGaN:Si sublayers are conductive, the entire n-type layer can remain as part of the finished LED device.