Study of the factors that limit the reliability of GaN-based LEDs at high temperature levels

This paper reports a study of the degradation mechanisms that limit the reliability of GaN-based LEDs at high temperature levels. The analysis has been carried out both at chip and package level. By means of specific tests, we demonstrate that high temperature treatment determines (i) the degradation of the properties of the ohmic contacts and of the semiconductor material at the p-side of the diodes and (ii) the degradation of the optical properties of the LEDs, due to the worsening of the reflective properties of the package.