Radiation-induced defects in MOS structures after irradiation with high-energy Ar, Kr, Bi heavy ions

Radiation damage in the MOS (metal-oxide-semiconductor) structures irradiated with Ar, Kr and Bi heavy ions with energies from 1 to 7.5 MeV/nucl. has been studied using charge deep level transient spectroscopy (Q-DLTS) and feedback charge capacitance voltage (C-V) techniques. Four dominant well-known deep levels such as vacancy-oxygen (VO) complex, divacancy (VV2−) in the double negative charge state and composite VV−+VSb complex were registered versus ion fluence and annealing temperature. It was shown that VO center concentration at the near-surface silicon substrate layer is determined by ion energy loss in elastic collisions and no effect of high-level electronic stopping power was detected. At the same time, the value of the positive radiation-induced defect charge in the oxide layer was decreased under Bi ions irradiation. Thermal treatment in air ambient at 250 °C restores CV characteristics of the MOS samples to that of un-irradiated state.