N-type gallium-nitride layer having multiple conductive intervening layers

US9012939B2 · kind B2 · utility

Assignee

• Kabushiki Kaisha Toshiba · JP

Inventors

• Zhen Chen · Stanford, US
• Yi-Min Fu · Taichung, TW

Key dates

• Filing date: Aug 2, 2011
• Grant date: Apr 21, 2015
• Expiry date: Jun 27, 2033

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10H20/825

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.