Vertical electrode GaN-based light-emitting diode fabricated by selective wet etching technique

In order to improve the device performance and productivity, a sapphire-etched vertical-electrode nitride semiconductor (SEVENS) light-emitting diode (LED) is fabricated by a selective wet-etching technique. The sapphire substrate is removed by chemical wet etching and transferred to a conducting Si substrate with a reflector metal. The SEVENS-LED exhibits excellent device performance. Integral light-output power is approximately 3.5 mW at a 20 mA junction current, which indicates a 6.6% external quantum efficiency (EQE). The light-output power was linearly increased with increasing junction current, and the peak wavelength was saturated even with a higher junction current. The enhanced performance of the SEVENS-LED is attributed to changing the lateral electrode to a vertical electrode and transferring a sapphire substrate to a Si receptor with a reflector metal. The SEVENS-LED technique is anticipated to be useful for improving the performance of GaN-based LEDs for future solid-state general illumination applications.