Reliability of InGaAs waveguide photodiodes for 40-Gb/s optical receivers

The reliability of 1.55-μm wavelength InGaAs waveguide photodiodes (WGPDs) fabricated by metal-organic chemical vapor deposition is investigated for 40-Gb/s optical receiver applications. Reliability for both high-temperature storage and accelerated life tests obtained by monitoring both the dark current and the breakdown voltage is examined. The median device lifetime and the activation energy of the degradation mechanism are extracted for WGPD test structures. The device lifetimes are examined via statistical analysis which is highly reliable in predicting the device lifetime under practical conditions. The degradation mechanism for the WGPD test structures can be explained by the formation of leakage current path by ionic impurities in the passivation layer on the exposed p-n junction. Nevertheless, it can be concluded that the WGPD test structures exhibit sufficient reliability for practical 40-Gb/s optical receiver applications.