Modeling Dark Current Degradation of Monolithic InGaAs/GaAs-On-Si Nano-Ridge Photodetectors

A comprehensive semi-empirical model is developed to elucidate the dark current dynamics in InGaAs/GaAs nano-ridge photodetectors directly grown on 300 mm Si; both constant voltage stress and recovery are investigated. Modeling results agree with the experimental data for all tested stress voltages and temperatures. Leveraging this model, device lifetime and maximum dark current degradation can be projected to optimize working conditions in different silicon photonic applications. Observations in the recovery phase disclose numerous contradictions against the reaction-diffusion model but are consistent with carrier emission/capture at pre-existing defect states, which modulates the generation-recombination current through trap-assisted tunneling.