Interface Effect And Properties Of CMN/CT Heterostructure Dielectric Thin Film

Microwave dielectric film, with the the advantages of high output power and suitability of microwave frequency applications, meets the need of miniaturization and high quality of integrated microwave devices. The interface play a crucial role in the heterogeneous dielectric film. The low-dimensional structures and properties of films can be controled by interface controlling effectively. For the interface effect in heterogeneous multi-oxide film, a number of important physical phenomena and mechanisms are still unclear, which is limited by the theoretical and experimental conditions and impeding the development of dielectric oxide thin film devices.CMN/CT heterogeneous multilayer dielectric film was prepared by spin-coating with Pechini method preparing precursor solution. The effects of arrangement, number of heterogeneous interface and interface treatment on the structure and properties of dielectric thin film were investigated. The results show that perovskite structure is difficult to form in the film with CMN first layer, since Mg2+ is not easy to enter as B-site. While CT layer is easy to growing on the substrate and can play the role of buffer layer, improving the growth of CMN on it. So the film with CT first layer has pure perovskite phase.Additionally, the heterogeneous interface can reduce the cumulative effect of roughness, improving the structure and surface smothness. And, with the forming of elastic displacement polarization layer, the heterogeneous interface improves the dielectric properties. So, with increasing of number of heterogeneoud interface, the microstructure and dielectric properties of films were improved.The CMN/CT heterogeneous multilayer dielectric films were treated by aqueous solution of HNO3 and H2O2, to investigate the effect of interface treatment on the structure and properties of the films. The results show that both of HNO3 and H2O2 will destroy the surface relaxation layer of CT layer and improve surface activity of the CT layer and growth and microstructure of the CMN layer, which will improve the properties of the films. HNO3 is easier to be control in two kinds of treatment agent. The extent of interface corrosion reaction is depended on the concentration of aqueous solution, while the type of it is depended on the processing time. So the processing time should be limited in 20s to avoid formation of the impurity, and the interface structure can be controled by changing the concentration of HNO3. The heterogeneous dielectric multilayer film with better dielectric properties was obtained by interface treatment. And the benefit of heterogenous interface on the dielectric properties of heterogenous films has been confirmed.