Innovative Fabrication of Wafer-Level InGaN-Based Thin-Film Flip-Chip Light-Emitting Diodes

In this letter, an innovative fabrication method for InGaN-based light-emitting diode (LED) was proposed, and the produced optical device was called the wafer-level InGaN-based thin-film flip-chip LEDs (wTFFC-LEDs). Packaging technologies, such as wafer-to-wafer bonding, laser lift-off, textured surface, and interconnection techniques, were applied to complete the device. Through this architecture, the absorption caused by electrodes in traditional vertical injection LEDs (V-LEDs) can be minimized, as well as the light extraction efficiency can be improved. Light-output power of wTFFC-LEDs (350 mA) was increased by 36.5% and 17.2% compared with the V-LEDs and flip-chip LEDs. Furthermore, the external quantum efficiency was also relatively enhanced by 36.3% and 15.5% higher than those of reference devices.