Analysis of the Degradation of Blu-Ray Laser Diodes

Reliability of GaN-based Blu-Ray Laser diodes subjected to constant current, constant optical power and high temperature stress is described in this paper. Several stress tests have been carried out at different temperature, current and optical power conditions. We demonstrate that the threshold current suffers an increase during both constant current and constant power stresses, and varies with a square root time law. We also show that the kinetic of the threshold current increase is strongly correlated to the kinetic of the sub-threshold emission degradation. This correlation indicates that stress induces an increase of non radiative recombination rate in the active layer. On the basis of the described experimental evidences, we attribute the degradation process to and electro-thermally activated generation of non-radiative defects.