EFFECTS OF RADIATION-DAMAGE IN SILICON P-I-N PHOTODIODES

The effects of radiation damage in two silicon p-i-n photodiodes fabri cated from high resistivity material have been studied. The devices ha ve been irradiated by 1 MeV neutrons to three different fluences up to 2.5 x 10(14) n cm(-2). Current, capacitance and charge measurements w ere performed prior to irradiation and soon after. Our results indicat e that the damage has degraded the charge-collection efficiency, that the devices have undergone type inversion from n-type to apparent p-ty pe at fluences as low as 3 x 10(13) n cm(-2), and that the substrate m aterial has become somewhat 'relaxation-like' after irradiation. It is suggested here that irradiated silicon is relaxation material.