© 2020, Springer Science+Business Media, LLC, part of Springer Nature.Determining the radiation effects on the basic electrical parameters of the fabricated high-dielectric MFIS structures, they were exposed to the high-energy 60Co γ-rays. For this purpose, the values of ideality factor (n), barrier height (ΦB) and series resistance (Rs) were extracted from the forward bias I–V data before and after irradiation by using various methods such as standard thermionic emission (TE) theory, Cheung’s and Norde functions. Additionally, the energy-dependent profile of surface states Nss was extracted by considering voltage dependence of n, ΦB and Rs and compared each other. Experimental results show that the reverse saturation current (Io), n and Rs values increase with increasing radiation dose, but ΦB decreases. When the value of Rs is considered in the calculation of Nss, they were found to be considerably decreased. The observed low discrepancies between Nss after irradiation show that the use of a high-dielectric ferroelectric interlayer leads to an increase in the resistance of MS to radiation. It is more important to fabricate radiation-resisted electronic device, especially in the satellites due to hard radiation in space. As a result, Nss, Rs and the existence of interlayer are more effectual on the I–V characteristics which must be considered in the electrical parameter calculation.