Improvement of efficiency and ESD characteristics of ultraviolet light-emitting diodes by inserting AlGaN and SiN buffer layers

Abstract

We have studied the effect of the AlGaN insertion and SiN buffer layers of ultraviolet light-emitting diodes (UVLEDs) on efficiency and electrostatic discharge (ESD) characteristics of UVLEDs grown by metalorganic chemical vapor deposition. The etching pit density was reduced from 3.6 x 10(8) cm(-2) in conventional samples to 1.6 x 10(7) cm(-2) in UVLEDs grown with the AlGaN insertion layer and SiN buffer layer. During the ESD tests at the negative biases of 3000 V, the live percentage of UVLEDs increased from 67% in conventional samples to 86% in samples with AlGaN insertion layers and SiN buffer layers. In addition, the device shows a low leakage current of 1.1 x 10(-8) A at -5 V and the light output power was 70% higher than the conventional UVLEDs at an injection current of 20 mA. (c) 2007 Elsevier B.V. All rights reserved.