Reactively sputtered HfO 2 and Ba(Zr 0.2 Ti 0.8 )O 3 (BZT)–HfO 2 dielectrics have been compared for high density metal–insulator–metal (MIM) capacitors, which are required for next generation radio frequency and analog/mixed-signal integrated circuits. Our experimental results indicate that the incorporation of BZT into HfO 2 can increase the dielectric constant of the insulator, reduce significantly the quadratic voltage coefficient of capacitance (α), and improve the uniformity of α. Furthermore, the conduction mechanisms of the capacitors with HfO 2 and BZT–HfO 2 insulators have been investigated, revealing that the Schottky emission is dominated in both capacitors, and the Schottky barrier under no electric field is extrapolated to be 0.54eV for the MIM capacitor with BZT–HfO 2 .