PZT THIN-FILMS GROWN BY MULTITARGET SPUTTERING - ANALYSIS OF THIN-FILM STRESS

A planar multi target sputtering approach was used to deposit Pb(Zr,Ti )O-3 (PZT) films with different composition on Pt bottom electrodes fo r the use in thin film pyroelectric IR detector arrays. Low stress fer roelectric capacitor stacks are needed in these devices, because the s ensing elements are arranged on thin micromachined membranes. PZT film s with a Zr content of 10 at% (10/90) and 48 at% (48/52) were analyzed in terms of thin film stress. PZT (10/90) films were found in a sligh t compressed state and PZT (48/52) under tensile stress after depositi on. Stress temperature curves were used to evaluate the Curie temperat ure of the films. From the stress temperature curves the spontaneous d istortion of the ferroelectric given by the lattice parameters can be extracted. The lower Curie temperature in combination with the smaller spontaneous distortion of the PZT (48/52) film is the reason for the difference in the stress state after deposition.