| Perovskite type lead zinc niobate(PZN)is a relaxor ferroelectric. PZN-based ceramics，with very high dielectric constant, large electrostrictrive strain and a tunable effectivepiezoelectric effect, have been wildly and will be used in the manufacture ofcapacitors, MLCCs, actuators and micro-electro-optic mechanics ete. With theincreasing demand of electronic equipment of reduced size and higher integrateddensity, electronic circuit miniatuirzation has been continuously made. And circuitdevices and components are required to have a compact design，high performance,and high reliability and be cost-effective. This trend leads to the R&D on thepreparation and the applications of PZN-based ferroelectric thin films.Sol-Gel technique was used to prepare mateirals with high puirty, compositionalstoichiometry and homogeneity in composition and microstructure. The low sinteringtemperature of the Sol-Gel deirved iflms make it possible to compact with integratedcircuits. Sol-Gel method is especially suitable to be used in prepairng thin films byspin coating. The processing of the thin film by sol-gel method is rather simple in alow pirce, without the need to use very expensive and complicated equipment andmachine. It has been widely employed in the preparation of ferroelectirc thin filmswith simple composition. Furthermore, thin films could be prepared in a large scaleusing the sol-gel method.0.7Pb (Zni/3Nb2/3)〇3-0.3PbTi03(PZNT) thin iflms, with a well-developed perovskitephase, have been prepared on Pt/Ti/Si02/Si substrate by a chemical solutiondeposiiton method. X-ray diffraction analysis shows that the PZNT thin films on Pt/Ti/SiC^/Si substrate are poly crystal line with (lll)-preferential oirentation.Pt/PZNT/Pt capacitors have been fabricated and a ferroelectric character with amaximu2m polairzation (Pmax) of35.36uC/cm and a remanent polarization (Pr) of162.84uC/cm. The temperature dependence of the ferroelectric properties was alsomeasured. The dielectric constant (satr) nd the dissipation factor (anS) at1kHz are305and0.075, respectively.The pulsed-laser deposition (PLD) technique is widely used in research anddevelopment for a large panel of thin films and is especially well-suited for oxidecompounds with complex composition. The PLD technique is very versatile for thinfilm engineeirng. Thin film deposition involves a material undergoing a phasetransition from a vapor phase, which is subsequently condensed onto a solid substrate.Different morphologies and structures may result when depositing from the vaporphase depending on the expeirmental parameters such as substrate surface,temperature and evaporation rate. The relationship between surface morphology anddeposition parameters has been widely investigated, including metals, inorganic andorganic thin film materials. However, the inlfuence of surface morphology has notbeen confirmed to be the dominating factor. Oxygen pressure and temperature ofsubstrates can considerably influence crystallization, oirentation, microstructure andelectrical properties of thin films. Pyrochlore0.9Pb(Zni/3Nb2^)03-0. lPbTi03(PZNT)thin films were prepared on (11l)Pt/Ti/Si02/Si substrates by pulsed laserdeposition(PLD) method. Well adhered and uniform thickness iflms were obtained,X-Ray Diffraciton studies showed the development of microcrystalline structure withincreasing of th’e substrates temperature, evidenced also by scanning electronmicroscopy. Compositions of the films obtained by SEM-EDS technique. Thedielectric constant and loss of the thin films were measured using an impedanceanalyzer (HP4194A). These pyrochlore-structured PZNT thin iflms show lowdielectric losses with a typical loss tangent as low as0.007, accompanied by arelatively high dielectric const (8r=126) v^iich is perfectly independent of frequency. |
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