Electrophysical parameters of test structures formed on high-resistivity silicon during manufacturing of p-i-n photodiodes have been investigated. Using specially constructed MIS test structures the following important electrophysical parameters of Si-SiO2 and Si-SiO2 -Si3 N4 systems characterizing the quality of silicon and semiconductor-insulator interface have been analyzed: surface generation velocity Sg, bulk generation life-time of minority carriers τg , fixed charge Qss and mobile charge Qi in dielectric. The influence of different types of insulators on Sg values and effect of voltage applied to the insulator on minority carrier generation velocity in MIS structures were found. The corellation between Qi and reverse currents in p-i-n photodiodes was revealed. High effectiveness of used test structures and proposed methodology for quality control of technological processes in p-i-n photodiodes processing have been established