Reliability of InGaAs/InP long-wavelength p-i-n photodiodes passivated with polyimide thin film

The long-term reliability of InGaAs/InP p-i-n photodiodes passivated with polyimide thin film was studied through a room temperature life test and through thermally accelerated life tests. No degradation in dark current was observed in a room temperature life test at a reverse bias of -15 V after aging for 7000 h. However, the dark current increased gradually in the accelerated life tests at 110°C, 130°C, and 150°C. It was confirmed that the activation energy of degradation in dark current was 0.85 eV and the average lifetime was estimated to be 10⁷h at room temperature. The dark current recovered in high temperature storage tests. The phenomenon of degradation and recovery was qualitatively explained by a model of accumulation and diffusion of mobile ions at a junction perimeter.