Frequency dependence studies on the interface trap density and series resistance of HfO2 gate dielectric deposited on Si substrate: Before and after 50 MeV Li3+ ions irradiation

We report the first investigation of the frequency dependent effect of 50 MeV Li3+ ion irradiation on the series resistance and interface state density determined from capacitance–voltage (C–V) and conductance–voltage (G–V) characteristics in HfO2 based MOS capacitors prepared by rf-sputtering. The samples were irradiated by 50 MeV Li3+ ions at room temperature. The measured capacitance and conductance were corrected for series resistance. The series resistance was estimated at various frequencies from 1 KHz to 1 MHz before and after irradiation. It was observed that the series resistance decreases from 6344.5 to 322 Ω as a function of frequency before irradiation and 8954–134 Ω after irradiation. The interface state density Dit decreases from 1.12 × 1012 eV−1 cm−2 before irradiation to 3.67 × 1011 eV−1 cm−2 after ion irradiation and further decreases with increasing frequency.