Characterization of Inversion Tunneling Current Saturation Behavior for MOS(p) Capacitors With Ultrathin Oxides and High- $k$ Dielectrics

The inversion current conduction mechanism for MOS(p) capacitors with ultrathin oxides was analyzed from another aspect of bulk traps in this paper. The relationships between deep depletion and generation-recombination current were also studied. It was found that the generation-recombination current due to bulk traps is proportional to the deep-depletion width and dominates the inversion tunneling current. Moreover, it was observed that the inversion tunneling current levels for SiO₂, Al₂O₃, and HfO₂ gate dielectrics were different. This discrepancy was explained with their energy band diagrams. Due to the small conduction-band offset of HfO₂, the gate dielectrics of HfO₂ show a worse capability to block the inversion tunneling current in the saturation region than Al₂O₃ gate dielectrics.