Failure mechanisms of gallium nitride leds related with passivation

Abstract

This paper analyzes the thermally-activated failure mechanisms of GaN LEDs under thermal overstress related with the presence of a PECVD SiN passivation layer. It is shown that the properties of the passivation layer can remarkably affect devices reliability during high-temperature stress: degradation mechanisms identified consist in emission crowding and series resistance increase, attributed to the thermally-activated indiffusion of hydrogen from the passivation to the p-layer, and subsequent p-doping compensation