Reliability of germanium avalanche photodiodes for optical transmission systems

Life tests are conducted using 620 Ge-APD's to confirm the 3-FIT reliability requirement at 25 years of service. First, the reliability assurance method for Ge-APD's is presented. Second, statistical treatments of life-test data are conducted with regard to wear-out and random failure modes, and the failure rate for each mode is estimated under the practical-use condition. This analysis confirms wear-out and random failure rates of far below 1 FIT and about 3 FIT's, respectively. Third, surge-endurance test results are also reported. Finally, the application of Au/Pt/Ti metal systems to Ge-APD's offers excellent metallization integrity against thermal stress compared with those having Al metallizations.