Impact of Irradiation Temperature, Doping, and Proton Energy on InGaAs Photodiodes

The increase in the dark current induced by proton irradiation is studied and the definition of an InGaAs damage factor is discussed. We investigate the dependencies of the radiation-induced dark current increase on the doping level, proton energy, and irradiation temperature. The doping level plays an important role in the dark current level because of electric field enhancement (EFE) effects in the thermal generation of carriers. If we call the increase in the dark current per proton the dark-current-related damage rate (DCDR), at low reverse bias, the less-doped photodiodes have higher DCDR, and at high reverse bias, the situation is inverted. The effect of the proton energy is discussed and the nonionizing energy loss (NIEL) scaling hypothesis is studied as a function of the reverse bias. At low reverse bias, we observe a higher DCDR for lower proton energy, which is consistent with the NIEL scaling hypothesis. At high reverse bias, however, the trend is inverted, and a lower DCDR is observed. Lastly, we observe a slightly higher DCDR for a lower irradiation temperature.