Light Extraction Enhancement of n-side up Light-Emitting Diodes without Electrodes Covering by Wafer Bonding and Textured Surfaces

Textured n-side-up GaN LED with interdigitated imbedded electrodes (IIE) eliminating the electrode-shading loss with high reflection mirror and double-side roughening on both p-GaN and undoped-GaN layers have been investigated. The epitaxial layers of the device are grown on (0001) sapphire substrates by metal-organic chemical vapor deposition. The devices are subsequently fabricated with wafer-bonding, laser lift-off, chemical dry/wet etching techniques. This n-side up structure was useful to enhance light extraction and increase the light output power. We compared the performance of the luminance intensity(at 350 mA injection current), which is 78.85 % and 115.38 % higher than those of the conventional structure and the p-side up structure with high reflection mirror on silicon substrate with electrode shading, respectively