Degradation of electron irradiated MOS capacitors

摘要

We have investigated the degradation of MOS structure due to high energy electron irradiation as a function of radiation dose and gate bias applied during the irradiation. Devices have been characterized by current-voltage measurements, in order to study charge accumlation also at the gate interface. Three types of oxide charge have been observed: the unstable positive charge, due to trapped holes induced by the electron irradiation; the negative charge in the oxide buld, deriving from capture of electrons injected during electrical measurements in radiation genergted traps; and border traps, at both oxide interfaces.