Sputtering of PZT thin films for surface micromachined IR-detector arrays

A planar, multi-target sputtering approach was used to deposit tetragonal P b(Zr,Ti)O-3 (PZT) films with Zr/(Zr+Ti) = 0.25 -0.3 on Pt bottom electrodes for the use in thin film pyroelectric IR detector arrays. Low stress ferro electric capacitor stacks are needed in:these devices, because the sensing elements are arranged on thin surface micromachined membranes, In-situ depo sited films exhibited the best electrical properties. Typical values for th e dielectric constant, the dielectric loss and the pyroelectric coefficient are 250, <0.01 and >2x10(-4) C/(m(2)K), respectively. Very strong imprint effects have been found in these films. Even after a heat treatment above t he Curie point a pyroelectric coefficient of > 2x10(-4)-C/(m(2)K) has been found. This is advantageous for possible high temperature processing steps after PZT deposition in pyroelectric detector device manufaction.