CHARGING PHENOMENON OF INSULATORS IN NEGATIVE-ION IMPLANTATION

The energy distribution of secondary electrons emitted from an insulat or during negative-ion implantation was measured. According to seconda ry-electron-energy analysis, the charging voltage of insulator was est imated from the measured energy distribution. The experimental results in negative-carbon-ion implantation showed that the charging voltages of a quartz glass plate and a photoresist film on silicon substrate a re several negative volts in the energy range from 5 to 35 keV and dec rease gradually with increasing ion energy. The low negative charging voltage of insulator and the most probable energy of the secondary-ele ctron energy distribution during negative-ion implantation are discuss ed using a charging model based on an electric double layer.