Mechanism for Leakage Reduction by La Incorporation in a \HfO2\/SiO2\/Si Gate Stack.

In this letter, we investigated a dominant mechanism for leakage reduction by the incorporation of La in a \HfO2\/SiO2 gate stack. We compared the experimental data for the leakage current for the La-doped \HfO2 \/SiO2 gate stack and the calculation for tunnel current through the gate stack, assuming that the La-induced dipole increases the barrier height of \HfO2 for electrons from the substrate. The agreement between the experimental data and calculated values strongly suggests that the main cause for leakage reduction is the effective barrier height modulation induced by the interface dipole. [ABSTRACT FROM AUTHOR]