Improvement of high reliability inverted rib-waveguide lasers by the observation of degradation mechanisms

IRW lasers were examined by electroluminescence, photoluminescence, cathodoluminescence, X-ray topography and electron-beam-induced current imaging. Dark line defects were observed in some devices and were found to be associated with lattice dislocations. These defects could be forced to grow by aging the devices and are associated with poorly lattice matched epitaxial growth. Dark spot defects were also observed in some devices and could be generated by exposure to extremely high current densities. These observation techniques can be used to screen out wafers that may produce defective devices later in processing, and complement stringent individual device validation tests.