A1InGaP LED having reduced temperature dependence

US7244630B2 · kind B2 · utility

Assignee

• Philips Lumileds Lighting Company LLC · US

Inventors

• Michael R. Krames · Los Altos, US
• Nathan Gardner · Provo, US
• Frank M. Steranka · San Jose, US

Key dates

• Filing date: Apr 5, 2005
• Grant date: Jul 17, 2007
• Expiry date: May 28, 2025

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/00014

Abstract

To increase the lattice constant of AlInGaP LED layers to greater than the lattice constant of GaAs for reduced temperature sensitivity, an engineered growth layer is formed over a substrate, where the growth layer has a lattice constant equal to or approximately equal to that of the desired AlInGaP layers. In one embodiment, a graded InGaAs or InGaP layer is grown over a GaAs substrate. The amount of indium is increased during growth of the layer such that the final lattice constant is equal to that of the desired AlInGaP active layer. In another embodiment, a very thin InGaP, InGaAs, or AlInGaP layer is grown on a GaAs substrate, where the InGaP, InGaAs, or AlInGaP layer is strained (compressed). The InGaP, InGaAs, or AlInGaP thin layer is then delaminated from the GaAs and relaxed, causing the lattice constant of the thin layer to increase to the lattice constant of the desired overlying AlInGaP LED layers. The LED layers are then grown over the thin InGaP, InGaAs, or AlInGaP layer.