Structure and Electrical Properties of Sputter Deposited (Ba_1-x,Sr_x) (Ti_1-y,Zr_y)O₃ Thin Films

(Ba_1-x,Sr_x)(Ti_1-y,Zr_y)O ₃ thin films as the dielectric materials for gigabit-scale dynamic random access memory was deposited by radio frequency magnetron sputtering. The films with controlled compositions were grown from a single target by the control of chamber pressure. When chamber pressure decreased, the dielectric constant of films decreased due to an increase of Zr content. The (Ba_1-x,Sr_x)(Ti_1-y,Zr_y)O₃ thin films prepared in this study show a dielectric constant of 380 ∼ 525 at 100 kHz. The films showed the decrease of leakage current as chamber pressure decreased and the leakage current density of films deposited above 10 mTorr was 10^-7 ∼ 10^-8 A/cm² at 200 kV/cm. The dominant transport mechanism of films was the interface limited Schottky emission conduction. The (Ba_1-x,Sr_x)(Ti_1-y,Zr_y)O₃ thin film appeared to be potential dielectric material for high density dynamic random access memory.