Deposition and Patterning Technique for Realization of Pb(Zr_0.52, Ti_0.48)O₃ Thick Film Micro Actuator

Abstract

The deposition technology for thin PZT (Pb(Zr0.52,Ti0.48)O3) layers has reached an advanced state in the application area of memory fabrication. On the other hand, the application of PZT layers for actuation of micro electromechanical system (MEMS) is not well established. A relatively thicker film is necessary for this application. Conventional preparation techniques provide poor deposition rates and the accumulated residual stress during deposition results in the deposited layer peeling off. Another difficulty lies in the low etching rate of the multilayered structure of SiO2/Ti/Pt/PZT. These are the reasons why we have studied thick PZT film preparation technology and efficient pattering processes. Thick film deposition processes include repeated multilayer coating by the sol-gel method, the excimer laser ablation deposition (ELAD), and the jet molding system (JMS). Pattering processes include RIE, ECR and deposition methods on a non-planar surface. The electrical properties of PZT layers were determined for microfabricated actuators.

Crystal structure and microstructure of lead zirconate titanate (PZT) thin films with various Zr/Ti ratios grown by hybrid processing

“…For use in these AFM cantilevers and microscanning mirror devices, high-quality 3-mm-thick PZT films on electrodes/substrates are desirable. Many fabrication techniques, such as the sol-gel method, pulsed-laser deposition (PLD) and jet print deposition, have been used to fabricate PZT films for microactuators [5]. However, it is not easy to obtain thick PZT films with good electrical properties by any of the fabrication techniques.…”

Growth of lead zirconate titanate thin films by hybrid processing: sol–gel method and pulsed-laser deposition

“…For use in those micro-scanning mirror devices and AFM cantilevers, in order to obtain a larger displacement, high-quality 1-3-mm-thick PZT films on electrodes/substrates are desirable. Many fabrication techniques, such as the sol-gel method, pulsed laser deposition (PLD) and jet print deposition, have been used to fabricate PZT films for microactuators [6]. However, it is not easy to obtain thick PZT films with good electrical properties by any of the fabrication techniques.…”

Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios

“…Our experimental results indicate that a mass ratio of around 4 is an optimal value to obtain thick (> 10 μm), dense, and crack-free PZT films with superior piezoelectric and dielectric properties in this process. There are mainly three reasons: (i) The dielectric constant (1200) and transverse piezoelectric values (−6 C/m 2 ) in the films with mass ratios around 4 are comparable to typical randomly oriented PZT thin film values 14,16. (ii) In the thick films with mass ratio > 4, the remanent polarization ( P r ) values of the films were observed to be saturated.…”