DEPOSITION OF SELF-POLARIZED PZT FILMS BY PLANAR MULTITARGET SPUTTERING

A planar multi target sputtering approach was used to deposit self pol arized PZT films on TiO2/Pt bottom electrodes for the use in thin film pyroelectric IR detector arrays. By using elevated substrate temperat ures of about 450 degrees C ''in situ'' growth of tetragonal PZT could be achieved. The films exhibited pyroelectric currents without poling . The pyroelectric coefficient was 2 x 10(-4) C/m(2)K, the dielectric constant was 300 and dielectric loss tan delta was 0.01. The self pola rization disappears after heating the sample to 600 degrees C. Stresse s were studied in the thin film processing for the bottom electrode an d the PZT film. The TiO2/Pt electrode is under high tensile stress of 900 MPa after preparation. PZT has a small compressive stress of -60 M Pa, the whole TiO2/Pt/PZT stack has a tensile stress of +80 MPa. This low stress level together with the self polarization and the good elec trical properties makes the films suitable for the use in pyroelectric detector arrays.