A flip-chip light emitting diode with enhanced efficiency. The device structure
employs a microcavity structure in a flip-chip configuration. The microcavity enhances
the light emission in vertical modes, which are readily extracted from the device.
Most of the rest of the light is emitted into waveguided lateral modes. Flip-chip
configuration is advantageous for light emitting diodes (LEDs) grown on dielectric
substrates (e.g., gallium nitride LEDs grown on sapphire substrates) in general
due to better thermal dissipation and lower series resistance. Flip-chip configuration
is advantageous for microcavity LEDs in particular because (a) one of the reflectors
is a high-reflectivity metal ohmic contact that is already part of the flip-chip
configuration, and (b) current conduction is only required through a single distributed
Bragg reflector. Some of the waveguided lateral modes can also be extracted with
angled sidewalls used for the interdigitated contacts in the flip-chip configuration.