Capacitance non-linearity study in Al2O3 MIM capacitors using an ionic polarization model

We have realized Al2O3 metal–insulator–metal (MIM) capacitors of three different thicknesses ranging from 7 to 20 nm, and performed capacitance versus voltage characterizations of the samples between 25 and 150 °C. The MIM capacitors presented increasing capacitance densities with temperature and parabolic C–V curves with a positive curvature. These results are widely observed in MIM capacitors with high-κ dielectrics such as HfO2[1], Ta2O5[2] or Y2O3[3], but non-linearity origins are rarely reported in literature. In this article, an attempt has been made to estimate the non-linearity of the permittivity in Al2O3 dielectric, assuming that electronic polarization did not contribute to the non-linearity.