Effects of electron irradiation damage on characteristics of silicon MOS diodes

Frequency dependence of C-V characteristics were found on n-type MOS devices irradiated with 25 KeV electron beam. In order to measure the surface-state density and surface potential, the saturation surface photovoltage method was used. The photovoltage method gave the smaller changes of surface potentials than Terman method. DLTS (Deep Level Transient Spectrum) method was also used for the measurement of deep traps by irradiation damage. These two methods indicated that the irradiation significantly induced the surface traps. The capture cross sections which were strongly dependent on energy level were found. (author)