Scaling of equivalent oxide thickness of atomic layer deposited HfO2 film using RuO2 electrodes suppressing the dielectric dead-layer effect

The influences of RuO2 metal gate on the dielectric performance of high-k HfO2 film on Si substrate were examined. The equivalent oxide thickness (EOT) of HfO2 film can be scaled down by ∼0.5 nm in the EOT range from 0.8 to 2.5 nm compared with the standard Pt gate case. This was attributed to the suppression of the dielectric dead-layer effect at the HfO2/RuO2 interface due to the possible ionic polarization of RuO2 within the screening length of the electrode. The estimated work function of RuO2 on HfO2 is ∼5.0 eV suggesting the appropriateness of RuO2 for p-transistor.

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