Sol-gel Precursor Monomer Legal System Preparation Of Pzt Ferroelectric Thin Film Technology And Performance Research

Among ferroelectric materials, lead zirconate titanate PbZrxTi1-xO3 (PZT) materials, in their perovskite structural form, display unique ferro-, piezo-, pyroelectric and electrooptic responses when subjected to an applied electric field, and many applications are under this consideration. They have been widely used for pyroelectric infrared detectors, optical switches, actuators, dynamic random access memories (DRAM), and non-volatile random access memories (FRAM).Various preparation techniques are available for the fabrication of PZT thin films, such as sputtering, electron beam and ion-beam deposition, PLD, MOCVD and Sol-Gel methods. Among these methods, the sol-gel process offers numerous advantages, including low processing temperature, excellent compositional control, uniform homogeneity, easy fabrication over large areas, low cost, etc.The raw materials are lead acetate trihydrate [ Pb(OCOCH3)2.3H2O], Zirconium nitrate [Zr(NO3)4.5H2O] and tetrabutyl titanate [Ti(OC4H9)4]. Because zirconium alkoxide is relatively expensive, we use inorganic zirconium salt replace zirconium alkoxide. In this study, a novel method of precursor-monomer and a reverse dip-coating method were designed for Sol-Gel film deposition. Compared to the conventional Sol-Gel method, the method has the advantages of simpler and precise composition control, easy change the Pb2+/Zr4+/Ti4+ stoichiometric, high reactivity, low synthesis temperature, without dry condition and distillation, easy fabrication homogenous films over any shapes devices, etc. PZT thin film was synthesized in Pb:Zr:Ti=1.1:0.52:0.48 with 0.2～0.4 M PZT precursor, containing 10 % mole excess Pb in order to account for the loss of Pb during the later thermal treatment. 2-methoxyethanol was used as solvent. The key of the new modified method is to prepare the three (Pb2+, Zr4+, Ti4+) stable and separated precursor–monomers, and with them to prepare PZT precursors that remain steady in standing storage.Using Pt/Ti/SiO2/Si as substrates,Pt is the common bottom electrodes. The top electrodes of Au with 0.6mm diameter were evaporated onto the PZT films through a shade mask for ferroelectric properties test. The crystallographic structures were examined by X-ray diffractometer (XRD). Surface morphology and microstructure of the films were investigated by AFM. The ferroeletric properties (remnant polarization Pr and coercive field Ec) of the PZT film were measured using an RT66A ferroelectric tester from Radiant Technologies.