A heteroepitaxial MIM-Ta2O5 capacitor with enhanced dielectric constant for DRAMS of G-bit generation and beyond

We demonstrate a novel MIM capacitor with a heteroepitaxial Ta2O5 dielectric, the permittivity of which is as high as 50. The heteroepitaxy of Ta2O5 on the Ru electrode changes its crystal symmetry from a conventional orthorhombic system to a hexagonal one. One-dimensional Ta-O-Ta chains along the c-axis bring about delocalized electrons, large polarizability and thus enhanced permittivity. This technology is promising for the application of Ta2O5 to the G-bit DRAMS, eliminating the need to use such exotic materials as BST and STO.