Effects of radiation damage in silicon p - i - n photodiodes

The effects of radiation damage in two silicon p - i - n photodiodes fabricated from high resistivity material have been studied. The devices have been irradiated by 1 MeV neutrons to three different fluences up to . Current, capacitance and charge measurements were performed prior to irradiation and soon after. Our results indicate that the damage has degraded the charge-collection efficiency, that the devices have undergone type inversion from n-type to apparent p-type at fluences as low as , and that the substrate material has become somewhat `relaxation-like' after irradiation. It is suggested here that irradiated silicon is relaxation material.