HfO2, Sr-Ta-O and Ti-Ta-O High-k Dielectrics for Metal-Insulator-Metal Applications

Atomic Vapor Deposition (AVD) technique was successfully applied for the depositions of amorphous HfO 2 , Sr-Ta-O and Ti-Ta-O thin films, which were investigated as alternative dielectrics to replace the standard SiO 2 or Si 3 N 4 dielectrics used in Metal-Insulator-Insulator (MIM) structures. Metal oxides were grown on 200 mm TiN/Si (100) substrates within the thermal budget of back-end-of-line (BEOL) process. Electrical properties, investigated after sputtering Au top electrodes, revealed that the main characteristics are different for each dielectric. On one hand, Ti-Ta-O based MIM capacitors possessed a dielectric constant of 50, which is more than a factor of 2 higher compared to the ones of Sr-Ta-O (20) and HfO 2 (18). On the other hand, Sr-Ta-O based MIM capacitors showed the lowest leakage current densities as well as the smallest capacitance-voltage linearity coefficients. Values as large as 5.9 MV/cm for the breakdown strengths are obtained for the HfO 2 based MIMs.