PYROELECTRIC CHARACTERISTICS OF A THIN PZT(40 60) FILM ON A PLATINUM FILM FOR INFRARED-SENSORS/

Very thin films of lead zirconate titanate (PZT) (40/60), 0.26 mu m or less, have been prepared on Pt-coated oxidized Si substrates (Pt/Ti/S iO2/Si) by a sol-gel process. These films were of high density with fi ne grains of about 0.2 mu m and annealed in the range of 600 degrees t o 700 degrees C in oxygen atmosphere. X-ray diffraction patterns taken on this film showed single-phase perovskite-type structure. Pyroelect ric and P-E hysteresis curve measurements, as well as measurements of the dielectric constant and loss tangent versus temperature and freque ncy, were performed. The influence of poling treatment on the dielectr ic and pyroelectric properties was also investigated, as well as diele ctric constants and pyroelectric properties. Dielectric constants and pyroelectric coefficients at room temperature were determined as 1300 and 840, and 68.0 and 10.3 nC/cm(2) . degrees C for the poled and unpo led PZT films, respectively The remanent polarization was 37.8 mu C/cm (2), and a coercive field was 146 kV/cm at a switching voltage of 16 V peak-to-peak and a frequency of 200 kHz. The remanent polarization an d coercive field were found to vary slowly with temperature. The mater ial was also difficult to depole. It is suggested that these films wil l be suitable for infrared detector applications.