CHARGE-PUMPING STUDY OF RADIATION-INDUCED DEFECTS AT SI-SIO2 INTERFACE

We have studied electrical defects of [100] Si-SiO2 interface created by gamma rays (Co-60) in submicrometer MOS transistors. By means of three-level charge pumping, the energy distribution of interface-trap parameters (emission times, cross sections, state density) has been determined in most of the silicon bandgap after different irradiations. We have shown the possibility of characterizing, using standard and three-level charge pumping, the oxide traps near the interface (border traps) induced by ionizing radiations. Their behaviour in emission regime is here investigated in terms of tunneling mechanism. We propose a new method, based on the three-level charge pumping technique, to determine the energy distribution of border traps.