In Situ Deep-Level Transient Spectroscopy and Dark Current Measurements of Proton-Irradiated InGaAs Photodiodes

In0.53Ga0.47As photodiodes were irradiated by 2.0- and 3.5-MeV protons at low temperature to study the effects of displacement damage. Defect spectroscopy and dark current measurements were performed in situ before room-temperature annealing could occur. It was found that annealing of the dominant mid-gap trap began as low as at 150 K. At room temperature, significant annealing of this trap occurred rapidly, annihilating more than half the traps on a time scale of tens of minutes. Because of annealing, the dark current at 250 K, a typical operating temperature for these devices, increased by up to twice the rate versus proton fluence than it did at 300 K. The results demonstrate that irradiation testing at room temperature is not the ideal approach to predicting in-flight device performance.