| Ferroelectric thin film with ABO3 perovskite structure has a broad prospect for its application in many fields due to their sufficient advantages including dielectric, piezoelectric, pyroelectric and ferroelectric properties. (Pb, Sr)TiO3 (PST) ferroelectric thin film is a hot research material because it has great dielectric tunability. However, high tunability of dielectric tunable thin film has to be stimulated by high electric field, and high electric field is always obtained under high voltage. The high voltage contradicts with the development of micro-electric component. At the same time, with miniturazation and integration of micro-electric devices, the requirement of performances of PST thin film becomes higher and higher. Obviusly, in order to adapt miniturazation tendency of micro-electric devices, the decrease of modulation voltage and improvement tunability of PST thin film become an important factor to using PST in related application field. Interdigital electrodes with small distance would decrease modulation voltage and improve tunability effectively. With the development of nano science, applications of electric-conducted nanowire are put forward. Considering low resistivity, high heat-stability and great compatibility with silicon integrated technology of titanium silicide, embedding TiSi nanowires as electrode of ferroelectric thin film could improve tunability and decrease modulation voltage. What’s more, the mechanism of the decrease in modulation voltage and improvement of tunability haven’t clearly announced until now, and thus the properties of thin film couldn’t be controlled greatly. Therefore, it’s important to research the composite electrode structure, and the further study about the formation mechanism of dielectric tunable thin film and announcing the property improvement mechanism are beneficial for the preparation and properties comtrol of thin film, and promote its applications in high-performance devices greatly.This paper reviewed preparation methods and applications of ferroelectric thin film with ABO3 perovskite structure, described dielectric tunability theory and current situation of dielectric tunable thin film based on fringing electric. Through the introduction of idea of using TiSi nanowires to generate large fringing electric field for stimulating tunability of PST thin film, TiSi nanowires/Ti5Si3 thin films were prepared by chemical vapor deposition method, and PST thin films were prepared on TiSi nanowires/Ti5Si3 thin film electrodes by magnetron sputtering method respectively. The phase structure, crystalline condition, morphology, and tunability were measured by XRD, FESEM and Agilent 4294A respectively. Effect of TiSi nanowires/Ti5Si3 thin film electrodes on structure formation and tunability of PST ferroelectric thin films was detailedly analysised. and the effect of TiSi nanowires/Ti5Si3 thin film electrode on tunability of PST ferroelectric thin films was simulated.Reserch shows that:As inducing effect of TiSi and Ti5Si3 structure, PST thin films sputtered on TiSi nanowires/Ti5Si3 thin films electrode have lower crystalline temperature and more phase content. This is favorable for the optimization of preparation, the improvement of properties, and the application to micro-electric devices of PST thin films. At the same time, modulation voltage of PST thin film sputtered on TiSi nanowires/Ti5Si3 thin film electrode decreases by about nine times at the same condition because of large fringing electric field generated by TiSi nanowires, and tunability improves by one time. Fringing electric field is affected by density and length of nanowires:the larger the nanowires density and the longer the nanowires, the larger intensity of fringing electric field. The application of fringing electric field to decrease modulation voltage and increase tunability is a great breakthrough for the application of ferroelectric thin film in dielectric tunable field. |
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