Stress Measurements of Pt/PZT/Pt Thin-Film Stack on Oxidized Silicon Substrate for Micro-Actuator

Author： Ichiki Masaaki Maeda Ryutaro Zhang Lulu

ISSN： 0015-0193

Source： Ferroelectrics, Vol.273, Iss.1, 2002-01, pp. : 83-88

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Abstract

The residual stresses in Pt/PZT/Pt thin-film stack coated on an oxidized Si substrate for micro-actuator were investigated. The thin-film stack was prepared with sputtering Pt/Ti films as bottom and top electrodes, and with sol-gel coating of PbZr_0.52Ti_0.48O₃ (PZT) film using a three-step heat-treatment process. The residual stresses in the film stack were then measured from the changes in the radius of curvature of the wafer. The Pt/Ti electrodes effect strongly to the residual stress in the thin-film stack and the largest stress was found after the first PZT layer's coating (≈−700 MPa, compressive) because of the simultaneous annealing of the Pt/Ti bottom electrode. The residual stress decreased from the second PZT layer's coating, and finally showed a compressive stress (≈−150 MPa) in the whole Pt/PZT/Pt thin-film stack.