Nucleation layer for improved light extraction from light emitting devices

US6683327B2 · kind B2 · utility

Assignee

• Lumileds Lighting US, LLC · US

Inventors

• Michael R. Krames · Los Altos, US
• Tetsuya Takeuchi · Yokohama, JP
• Junko Kobayashi · San Jose, US

Key dates

• Filing date: Nov 13, 2001
• Grant date: Jan 27, 2004
• Expiry date: Nov 13, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10H20/0137

Abstract

A light emitting device including a nucleation layer containing aluminum is disclosed. The thickness and aluminum composition of the nucleation layer are selected to match the index of refraction of the substrate and device layers, such that 90% of light from the device layers incident on the nucleation layer is extracted into the substrate. In some embodiments, the nucleation layer is AlGaN with a thickness between about 1000 and about 1200 angstroms and an aluminum composition between about 2% and about 8%. In some embodiments, the nucleation layer is formed over a surface of a wurtzite substrate that is miscut from the c-plane of the substrate. In some embodiments, the nucleation layer is formed at high temperature, for example between 900° and 1200° C. In some embodiments, the nucleation layer is doped with Si to a concentration between about 3e18 cm−3 and about 5e19 cm−3.