Preparation and dielectric properties of compositionally graded lead barium zirconate thin films

Both up and down compositionally graded (Pb1−xBax)ZrO3 (PBZ) thin films with increasing x from 0.4 to 0.6 were deposited on Pt(1 1 1)-buffer layered silicon substrates through a sol–gel method. The microstructure and dielectric properties of graded PBZ thin films were investigated systemically. X-ray diffraction patterns confirmed that both PBZ films had crystallized into a pure perovskite phase after annealed 700 °C. Electrical measurement results showed that although up graded films had a slightly larger tunability, dielectric loss of down graded films was much lower than that of up graded films. Therefore, the figure of merit of down graded PBZ films was greatly enhanced, as compared with up graded films. Moreover, down graded PBZ thin films also displayed excellent temperature stability with a smaller temperature coefficient of capacitance (TCC) of −0.59 × 10−3 °C−1 from 20 °C to 80 °C.