Characterization and comparison of the charge trapping in HfSiON and HfO₂ gate dielectrics

摘要

Charge trapping in HfSiON and HfO₂ gate dielectrics was studied using both DC and pulsed I_D-V_G characterization techniques. The data shows a significant amount of hysteresis in HfO₂ but negligible instability in HfSiON. Constant voltage stress measurements of HfO₂ and HfSiON films show that the threshold voltage shift in HfO₂ films is as much as 10 times higher than that of HfSiON. Further, modeling of the time dependence of the threshold voltage shows that the trap capture cross section responsible for the instability of HfO₂ films is 10 times higher than the trap capture cross section of HfSiON. Our data indicate that amorphous HfSiON has better electrical stability than HfO₂.