Patent ID: 6969874
Filing Date: 2005-11-29
Classification: H01L

Abstract:
1. A flip-chip light emitting diode with enhanced light extraction efficiency, comprising: a transparent growth substrate; a first n-type buffer layer overlaying the transparent growth substrate; a partially reflective mirror layer overlaying the first n-type buffer layer; a second n-type barrier layer overlaying the partially reflective mirror layer; a light emitting active layer overlaying the second n-type barrier layer; a p-type barrier layer overlaying the light emitting active layer; a highly reflective p-contact pad overlaying the p-type barrier layer; and an n-contact pad overlaying the first n-type buffer layer; wherein the n-contact pad and the highly reflective p-contact pad are disposed on the same side of the light emitting diode; wherein a resonant optical microcavity is disposed in-between the partially reflective mirror layer and the highly reflective p-contact pad; wherein the highly reflective p-contact pad comprises a reflective metal stack comprising: wherein the P-doped barrier layer comprises p-doped GaN or p-doped AlGaN; wherein the partially reflective mirror layer comprises a distributed Bragg reflector; wherein the distributed Bragg reflector comprises alternating layers of AlGaN and GaN; and wherein the distributed Bragg reflector has a reflectivity equal to approximately 25% to 40%.