GaN-Based Light-Emitting Diode with Indium–Tin–Oxide and Vertical Electrode

Abstract

A sapphire-etched vertical-electrode nitride semiconductor (SEVENS) light-emitting diode (LED) is fabricated by a selective wet-etching technique. The SEVENS-LED has an indium–tin–oxide (ITO) transparent metal electrode (TME) and a sapphire via hole. The SEVENS-LED exhibits excellent device performances compared with a lateral-electrode (LE) GaN-based LED formed on a sapphire substrate. The light-output power of the SEVENS-LED is ∼7 mW at a 20 mA junction current, which means 13% external quantum efficiency (EQE). The electrostatic discharge (ESD) test shows excellent ESD characteristics of the SEVENS-LED compared with those of the ITO LE-LED. The reverse ESD amplitude of SEVENS-LED is approximately 200 V, which is two times higher than that (∼100 V) of the ITO LE-LED. These improvements of ESD properties are attributed to the change of the lateral electrode to a vertical electrode, without requiring the transfer of the sapphire substrate to a conducting substrate.