Dielectric properties of radio frequency magnetron sputter deposited zirconium titanate-based thin films

We have studied the dielectric properties of thin film zirconia-titania-based mixed oxide compositions. Films of different Zr/Ti ratios were developed by radio frequency magnetron sputtering, and the effect of dopant addition to the composition were also investigated. We present a comparison of the electrical properties of zirconium titanate thin film capacitors in metal-insulator-semiconductor and metal-insulator-metal structures, and discuss the effect of process parameters on film properties. Stoichiometric (1:1 Zr:Ti), 320 Angstrom zirconium titanate films on silicon exhibited an effective dielectric constant of 17 at 1 MHz. This is equivalent to an SiO2 thickness of 73 Angstrom. For 2500 Angstrom thin zirconium titanate films on silicon, the dielectric constant was determined to be 37 at 1 MHz. On platinized silicon, the dielectric constant of 450 Angstrom zirconium titanate films was 33. This corresponds to an equivalent SiO2 thickness of 53 Angstrom. Direct current resistivities improved by nearly two orders of magnitude by modifying the film composition with an addition of tin oxide. Tin modification also resulted in a significant improvement in the film de breakdown characteristics, and we have achieved dielectric breakdown field greater than 7 MV/cm. Zirconium titantate-based thin films display high resistivity and high dielectric constant, and are highly promising for ultra-large scale integration applications. These films provide large capacitance in small area, and hence, higher charge storage capacity.