Numerical and analytical modeling of bulk and surface generation recombination currents in InGaAs/InP SWIR photodiodes

Understanding the failure mechanisms in high performance detector arrays is critical for meeting the demands for a given application. For SWIR sensing, the detector requires the highest sensitivity possible to operate under photon-starved conditions. Using a 3D drift-diffusion model, we simulate the influence of heterointerface traps on the dark current in In0:53Ga0:47As / InP p-on-n planar heterojunction photodiodes. We calculate how the dark current changes with junction area, and show that it increases linearly with junction radius when the device is limited by surface recombination. An analytical model is developed to understand the geometric dependence of both bulk and surface generation/ recombination currents. Finally, insight on mitigation strategies and possible impact on quantum e ffi ciency are both discussed.