High field nonlinear relaxational polarization of aluminum- and hafniumoxide

Summary

We start here with a comparison of the frequency and the high electric field dependent capacitance of HfO2 and Al2O3 based metal-insulator-metal MIM capacitors. A nonlinear relaxational polarization is revealed for both oxides in DC bias fields of up to 2 MV/cm. The nonlinearity of HfO2 is higher than that of Al2O3. Furthermore Al2O3 capacitor devices were annealed to various temperatures, 366, 411 and 455 K. Their capacitance measurements were conducted at room temperature. It is illustrated that increasing the annealing temperature leads to decrease the capacitance nonlinearity in high fields. This way the nonlinearity can be reduced up to 80% of its initial value. An asymmetric double well potential model is applied to interpret the experimental data. These experiments illustrate an important role of hydrogen in asymmetric double wells contributing to the relaxational polarization of metal oxides.

Additional informations

Authors

L. KANKATE

Keywords

Dielectric relaxation, polarization, oxide films, high fields