III-nitride light emitting devices grown on templates to reduce strain

US7547908B2 · kind B2 · utility

Assignee

• Philips Lumilieds Lighting Co., LLC · US

Inventors

• Patrick N. Grillot · San Jose, US
• Nathan Gardner · Provo, US
• Werner Goetz · Palo Alto, US
• Linda Romano · Sunnyvale, US

Key dates

• Filing date: Dec 22, 2006
• Grant date: Jun 16, 2009
• Expiry date: Apr 11, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F71/127

Abstract

In a III-nitride light emitting device, the device layers including the light emitting layer are grown over a template designed to reduce strain in the device, in particular in the light emitting layer. Reducing the strain in the light emitting device may improve the performance of the device. The template may expand the lattice constant in the light emitting layer over the range of lattice constants available from conventional growth templates. Strain is defined as follows: a given layer has a bulk lattice constant abulk corresponding to a lattice constant of a free standing material of a same composition as that layer and an in-plane lattice constant ain-plane corresponding to a lattice constant of that layer as grown in the structure. The amount of strain in a layer is |(ain-plane−abulk)|/abulk. In some embodiments, the strain in the light emitting layer is less than 1%.