Dielectric Properties of PCB Embedded Bismuth-Zinc-Niobate Films Prepared by RF Magnetron Sputtering

A novel bismuth zinc niobate (Bi_1.5Zn_1.0Nb_1.5O₇, BZN) thin film was studied as an embedded capacitor. The BZN thin films were prepared on copper based substrate by RF sputtering, which is compatible with low-temperature PCB processing. The films without any heat treatment were composed of an amorphous phase. Dielectric properties of the BZN thin films measured using Au/BZN/Cu structure were strongly dependent on deposition conditions. Very high dielectric constant of 87 was obtained for the BZN thin films even though they are in amorphous phase. The capacitance density and leakage current were 218 nF/cm² and less than 1 uA/cm² at 3 V, respectively. The process-compatibility of BZN thin films with PCB process was also studied.