Pyroelectric Peyformance Evaluation of Pure PZT and Alternately Deposited PZT/PT Thin Films

To improve the performance of the PZT thin films, each PZT and PT layer was alternately deposited on a Pt/Ti/Si₃N₄/SiO₂/Si substrate by a modified sol-gel solid precursor technique. For comparison, PZT thin films were also prepared with an identical method under the same conditions. XRD measurement revealed that the diffraction pattern of the multilayer film was due to the superimposition of the PZT and PT patterns. At 1kHz, a dielectric constant of 389 and 558, a dielectric loss of 1.2% and 1.1 % were obtained for the PZT/PT and PZT thin films, respectively. If we consider the PT dilelectric constant to be 260, it is clear that the dielectric constant of alternately deposited PZT/PT thin lilms was well adjusted. The PZT/PT thin film showed a low dielectric constant and a similar dielectric loss compared with those of the PZT film. The figures of merit on detectivity for the PZT/PT and PZT thin films were 20.3xlO^-6Pa^-1/2, and 18.7X10^-6Pa^-1/2. and the figures of merit on voltage response were 0.038㎡/C and 0.028㎡/C, respectively. The high figures of merit for the PZT/PT film were ascribed to its relatively low dielectric constant when compared to the PZT thin films.