Improved ESD characteristic of GaN-based blue light-emitting diodes with a low temperature n-type GaN insertion layer

Abstract

We demonstrate the improvement of the electrostatic discharge (ESD) characteristic of GaN-based blue light-emitting diodes (LEDs) by inserting a low-temperature n-type GaN (LT-nGaN) layer between the n-type GaN layer and InGaN/GaN multiple quantum wells (MQWs). The ESD endurance voltage > 4000 V pass yield is increased from 9.9% to 74.7% when the LT-nGaN insertion layer is applied to the GaN/sapphire-based LEDs. The LT-nGaN plays a role of buffer layer for MQWs, which reduces the strain of MQWs and improves the interface quality. Moreover, we also demonstrate that ESD characteristics of the LEDs with LT-nGaN insertion layer growth in N2 are much better than that in H2, which further confirm that the improvement of ESD characteristics is due to the strain relaxation in MQWs. Optoelectrical measurements show that there is no deterioration of the electrical properties of LEDs and the light output power of LEDs at an injection current of 20 mA is improved by 13.9%.