Electron Irradiation Effects on Atomic Layer Deposited High-k Gate Dielectrics

Abstract

Electron radiation effects on the electrical properties of Al2O3 and HfO2-based MIS capacitors have been studied. High-k dielectrics were grown by atomic layer deposition, and capacitors were exposed to three different electron radiation doses. Capacitance-voltage, deep-level transient spectroscopy, conductance transients, flat-band voltage transients and current-voltage techniques were used to characterize the samples. In all cases, positive charge is trapped in the dielectrics after irradiation. Insulator/semiconductor interface quality can be improved for low irradiation doses. However, for high doses interface quality worsens. Irradiation always degrades the dielectric layers in terms of gate leakage current.