Reliability of etched-mesa buried-heterostructure semiconductor lasers

This paper reviews the effects of metal-contact-type buried-heterostructure (BH) interfaces and substrate quality on the reliability of BH distributed-feedback (DFB) InGaAsP/InP lasers. For electrical contact, the significant improvement in device lifetime using Au/Ti/Pt/Au p-metallization over Au/Zn/Au will be shown. The temperature and current-density-acceleration factors of the diffusion of Au spiking during life-test aging are estimated. For BH interfaces, performance degradation related to damage on the mesa sidewall generated during the etching process and regrowth processes will be discussed. For the substrate, various failure mechanisms related to the formation and propagation of dark-spot defects (DSD) will be reviewed. The authors discussed various process remedies and show that a thicker buffer may lead to reliability-performance improvement with experimental results. This paper concludes with a brief description of the time-to-failure extrapolation methodology used.