Abstract. (Pb, La) (Zr, Ti)O 3 (PLZT) antiferroelectric thick films were deposited on Pt (111)/ Ti/SiO 2 /Si (100) substrates via sol-gel process. X-ray diffraction (XRD) analysis indicated that the films derived on Pt (111)/ Ti/SiO 2 /Si (100) substrates showed strong (111) preferred orientation. The Bulk and Surface silicon of micromachining process were employed in the silicon-based antiferroelectric thick film microcantilever fabrication, such as wet chemical etching for PLZT, inductive couple plasmas (ICP)for silicon etching, platinum etching and so on. Challenges such as Pt/Ti bottom electrode and morphology of PLZT thick film were solved, the integration of functional antiferroelectric materials and MEMS technology, provide a new way of thinking for the design and manufacture of micro-actuators.
IntorductionAntiferroelectric(AFE) materials have received extensive increasing attention due to their potential applications in the integrated devices, such as large displacement micro-actuators and high-strain micro-transducers. [1]. The AFE phase can be induced into ferroelectric (FE) phase under the external sufficient electric field. For the unit cell of the FE phase is larger than that of AFE phase, so the volume of the material changes together with the phase transition [2,3]. W.Y Pan et al [4,5] reported that the strain of (Pb,La)(Zr,Ti,Sn)O 3 antiferroelectric ceramics can reach 0.85%. For (Pb,La)(Zr,Ti,Sn)O 3 bulk-type AFE ceramics, the switching time of phase transition is about 2us, of which is less than 300ns for the AFE thick film [6].Compared with other methods, such as metal organic chemical vapor deposition (MOCVD) [7] techniques, electron beam deposition(EBD) [8]and so on, sol-gel [9] process is one of the most popular technique to fabricate Pb-based antiferroelectric thick films on platinum electrodes because of its simple process, lower price, accurate chemical control and large area production.In this paper, a microcantilever structure is adopted as the driving component. The micro-patterning of PLZT antiferroelectric thick film and the top/bottom electrodes played a key part during the process of preparation, the micro-patterning technology include chemical etching, reactive ion etching, and lift-off technology etc. In this study, the wet chemical etching was introduced for PLZT, inductive couple plasmas (ICP) for silicon etching and sputtering process for electrodes. Series of these processes have successfully realized micro-patterning of the sensitive cell. The difficulties of electrodes etching were solved, which laid a good foundation for further study of silicon-based antiferroelectric thick film micro-actuators.
Experimental procedure and analysisThe flow chart, shown in figure.1, depicted the sol-gel deposition process for PLZT antiferroelectric films. At first, acetate trihydrate Pb(CH 3 COO) 2 ·3H 2 O with 10% excess in order to compensate Pb loss during annealing and prevent the formation of the pyrochloren phase, lanthanum acetate hydrate La(CH 3 COO) 3 ·H 2 O and acetate acid CH 3...