Structural and Electrical Characteristics of Ba(Zr_0.12Ti_0.88)O₃ Thin Films Deposited on LaNiO₃ Electrode by RF Magnetron Sputtering

Abstract

Sputter-deposited LaNiO 3 (LNO) was used as a bottom electrode for the deposition of 50-nm-thick Ba(Zr 0.12 Ti 0.88 )O 3 (BZT) thin films on Pt/Ti/SiO 2 /Si substrates by rf magnetron sputtering. Highly intense and (100)-oriented perovskite films of BZT were grown on a (100)-textured LaNiO 3 electrode by rf magnetron sputtering at temperatures varying from 300 to 550°C in an atmosphere of Ar/O 2 =50/50, or in Ar/O 2 atmosphere varying from 50/50 to 90/10 at 400°C. The BZT films had a very smooth surface and an interface coherently bonded to the LNO electrode. X-ray diffraction (XRD) revealed that the crystallinity and lattice constant of the BZT films changed with deposition condition. With improvement in film crystallinity, the dielectric constant of the BZT films increased. A value of k =210–250 was obtained for films deposited at 400–450°C in the Ar/O 2 =50/50 atmosphere, and more importantly, a highly insulative characteristic of low leakage current of ∼10 -9 A/cm 2 with a high onset field of ∼1 MV/cm was achieved for the BZT capacitors. The leakage current was also significantly affected by preparation conditions of the top and bottom electrodes of the BZT capacitors.