A study on the gamma and swift heavy ion irradiation-induced effects on the electrical properties of TaOx-based MOS capacitors

In this work, we present a detailed study on the effects of energetic ions and gamma irradiation on the performance of non-stoichiometric tantalum oxide (TaO_x) based Metal Oxide semiconductor (MOS) capacitors. The leakage current is found to increase after a critical fluence (5E12 ions/cm²) of 120 MeV Ag ion irradiation. Whereas the accumulation capacitance decreased drastically upon the initial fluence and the hysteresis loop is intact even at higher doses. The order of leakage current and accumulation capacitance remained almost the same in the case of gamma irradiation though there are minor variations as a function of dose. Photoluminescence studies indicated specific changes in the density of various types of defects in both ion and gamma irradiation samples. The observed changes in the electrical properties of these devices are consistent with the nature and density of various defects. The study suggests that the TaO_x-based MOS devices can sustain higher doses and are capable of working in radiation-harsh environments.