High dielectric constant (Ba0.65Sr0.35)(Ti0.41Zr0.59)O3 capacitors for Gbit-scale dynamic random access memory devices

High dielectric constant (Ba0.65Sr0.35)(Ti0.41Zr0.59)O3 (BSTZ) thin films were prepared on Pt/Ti/SiO2/Si substrates at 500 °C from the target composition of (Ba0.65Sr0.35)(Ti0.65Zr0.35)O3 by the rf magnetron sputtering technique and evaluated as a function of annealing temperature. The 95-nm-thick BSTZ films showed a dense morphology with a small grain size and an increase of the dielectric constant with increasing annealing temperature. The dielectric constant and dissipation factor of BSTZ films annealed at 750 °C were 610 and 0.025 at an applied frequency of 100 kHz, respectively. The leakage current density of films increased with increasing annealing temperature, and the value for films annealed at 750 °C was about 9.0×10−9 A/cm2 at 400 kV/cm. The dominant transport mechanism of BSTZ films was interface-limited Schottky emission. The BSTZ films formed by rf sputtering are attractive for Gbit-scale dynamic random access memory applications.