Reliability of InGaAs Photodiodes for SL Applications

Abstract

A major objective of the TAT-8 submarine cable development program is the reliability assurance of its critical components. A relatively new device, the InGaAs photodiode, is used as the detection element in optical receivers and as the monitor of laser output in optical transmitters. In this paper, we describe a comprehensive reliability program aimed at assessing and assuring the reliability of InGaAs photodiodes. A major portion of this work has involved device operation at overstress conditions. Results to date indicate that for receiver photodiodes a device design exists which is predicted to meet a 1-FIT reliability objective. Tests of monitors of similar design are in progress. Critical to the success of the reliability assurance program is the ability to identify weak devices which are likely to fail early in the system life cycle. A conventional high-temperature burn-in is shown to be impractical, and it would not necessarily remove devices which fail by low activation energy processes. Overvoltage provides a means of accelerating such failure mechanisms. A “purge” using a combination of accelerants (high temperature and overvoltage) is shown to have considerable promise in failing weak devices, while inducing significant changes in those devices which subsequently fail early in a life test (elevated temperature at normal bias conditions). Devices which are unaffected by the purge are shown by extended life tests to be robust devices which have a high probability of meeting TAT-8 requirements.