Light emitting device having a finely-patterned reflective contact

摘要

The invention is an AlInGaN light-emitting device (LED) that includes a p-type contact made of highly-reflective material with closely-spaced openings that increase light extraction efficiency. The minimum dimension of the openings is ¼ of the wavelength of the emitted light and is preferably comparable to the distance current flows laterally in the p-layers of the device. The openings in the metal occupy 20-80% of the top surface of the contact and are finely spaced to achieve transparency and uniform light emission. An optional dielectric encapsulant may be deposited over the p-type contact to improve the contact's adhesion by tacking it down at regular intervals, and to improve light extraction. The surface of the epitaxial layers may be etched in the openings to scatter light in the semiconductor, increasing light extraction. A reflective layer may be applied to the bottom surface of the LED to increase the light extraction efficiency.