A study on the reverse-bias and ESD instabilities of InGaN-based green LEDs

Therefore the aim of this paper is to describe a detailed investigation on the reverse-bias degradation of GaN-based LEDs. The results described in this paper indicate that: (i) under reverse bias, LEDs can show a weak luminescence signal, due to the recombination of carriers injected in the quantum-wells; (ii) reverse-bias stress can induce the degradation of the electrical characteristics of the LEDs (increase in reverse-current, decrease in breakdown voltage), due to the generation of point defects in proximity of pre-existing defective regions. (iii) Furthermore, our tests indicate that the defective regions responsible for reverse-current conduction can constitute weak points with respect to ESD events: ESD failures are determined by the shortening of the junction in proximity of one of the defective sites responsible for reverse-current conduction.