Electric Field-Enhanced Generation Current in Proton Irradiated InGaAs Photodiodes

Dark current degradation due to 49.7 MeV proton irradiation is studied on lattice-matched indium gallium arsenide (InGaAs) p-i-n photodiodes. This degradation is described in terms of electric field-enhanced Shockley-Read-Hall (SRH) generation current in the depletion region. In this article, we present a model of the radiation-induced generation current which includes the role of the electric field through the generation rate field enhancement factor (GRFEF). Using a combination of dark current-voltage and capacitance-voltage measurements, an experimental GRFEF is extracted for the thermal generation rate. This GRFEF has been used to define a new damage factor for InGaAs at low electric field that has been compared to previous literature studies. As a final result, the low-field generation lifetime degradation as a function of the fluence has been extracted.