Temperature dependence of the piezoelectric response in lead zirconate titanate films

The temperature dependence of the effective transverse piezoelectric coefficient (e(31,f)) in lead zirconate titanate (PZT) thin films was measured between -55 and 85 degreesC. e(31,f) was calculated by simultaneously monitoring the piezoelectric charge output and strain in the film during wafer flexure. This method was used to characterize the temperature dependence of e(31,f) in PZT films with 2, 4, and 6 mum thickness and 40/60, 52/48, and 60/40 Zr/Ti ratios. parallel toe(31,f)parallel to was found to increase with temperature and average increases were 46%, 32%, and 12% for films with PZT 60/40, 52/48, and 40/60 compositions, respectively. Measurement uncertainty ranged from +/-3%-12%. The measured temperature dependences of e(31,f) were consistent with the rapid rise in intrinsic d(31) as T-c is approached, suggesting that they were controlled by intrinsic contributions. Additional contributors to the measured variation in the PZT film piezoelectric response over the measured temperature range were identified. Changes in film elastic properties could have decreased measured e(31,f) values by to 1%-4% in heating from -55 to 85 degreesC. Changes in the biaxial film stress with temperature were expected to account for 1%-3% of the measured increase in e(31,f) from -55 to 85 degreesC. (C) 2004 American Institute of Physics.