Study Of Preparation And Microstructure Characterization Of Barium Zinc Niobate Microwave Dielectric Ceramics Thin Films By RF Magnetron Sputtering

Recently,with the rapid development of electronic and microelectronic industry,microwave communication industry has grown up swiftly,which largely accelerates the study of microwave materials and devices.The development of microwave communication devices has become high integration of microwave frequency devices and the promotion of work efficiency.Currently there are mainly three types of microwave frequency devices:semiconductor devices,surface acoustic devices(SAW,FBAR,etc) and microwave dielectric devices.The advantages of low loss,stable and reliable properties,low cost and being suitable for microwave high frequency range have make microwave dielectric devices the hot topics of domestic study and abroad.At present,the study at home and abroad mainly focuses on bulk devices.However,the minimum size of bulk devices isλ/4,which can't meet the requirement of integration and high property,and it impedes the application of microwave dielectric,thus providing a wide platform for microwave dielectric ceramics thin films in the fields of microwave integrated circuit and microwave integrated devices.As a very important fabric and functional thin film material,microwave dielectric ceramics thin films have got more and more attention.Because they have much larger surface acreage than the bulk ones,and the special surface structure can modulate the asymmetry and dissymmetric structure of surface electric charge distributing,there are unique excellent performances of them. The application of microwave dielectric ceramics thin films to the fields of microwave dielectric thin film devices not only can reduce the electrode spoilage to get the high performance devices, but also meet the requirements of devices chip integration,which has a significant practical meaning on the realization of integration and high quality of microwave devices.Strontium Barium Zinc Niobate((Ba_xSr_1-x)(Zn_1/3Nb_2/3)O₃,x is the mole fraction, 0≤x≤1,which is short for BSZN) is the microwave dielectric ceramics with cube perovskite structure.Under very high microwave frequency,BSZN has the advantages of very low dielectric loss,extreme low resonance frequency temperature coefficient,etc,so there are many important and potential applications to the satellite communication,radar,and mobile communication system.However,BSZN bulk materials can't meet the requirements of integration,which impedes the application of the microwave dielectric devices,so it has a very important practical meaning on the study of BSZN thin films.There are many methods to prepare the dielectric thin films,which mainly are Sol-Gel, MBE,PLD,RF magnetron sputtering,etc.Among these methods,with the advantages of low loss,high speed,being suitable for C axis,being able to prepare practical large acreage films with very low cost,etc,RF magnetron sputtering is one of the most commonly used methods to prepare dielectric thin films,for good controllability and repeatability of the thickness of the thin films,and high purity of the thin films can be gained.However,there are few study at home and abroad in terms of microwave dielectric ceramics thin films prepared by,so it has relatively wide study fields.The study of this paper concerns two aspects:firstly,RF magnetron sputtering technique and thermal annealing technique are employed to prepare Ba_0.3Sr_0.7(Zn_1/3Nb_2/3)O₃ thin films on the substrate of single crystal SiO₂(110).However,in the process of sputtering and annealing, volatilization of ZnO and saturated vapor pressure of elements probably result in the preparation of mixed phase films.Then orthogonal test was conducted to explore the preparation technology of(Ba_0.3Sr_0.7)(Zn_1/3Nb_2/3)O₃ thin films and to optimize parameters.Meanwhile,by means of many electron microscopy,as well as X ray diffraction,the morphology,microstructure and components of the thin film structure were analyzed and expounded,as it mainly illustrates as follows:(1) RF magnetron sputtering technique and thermal annealing technique are employed to prepare(Ba_0.3Sr_0.7)(Zn_1/3Nb_2/3)O₃ thin films on the substrate of single crystal SiO₂(110).In the process of the test,orthogonal test was conducted to optimize RF magnetron sputtering technique to get better quality of thin films parameters,which can provide basis for the study of BSZN thin films.(2) As for the thin films structure samples to be prepared,electron microscopy was mainly analyzed and expounded,which includes scanning electron microscope(SEM),transmission electron microscopy(TEM),atomic force microscopy(AFM),x ray diffraction(XRD),selective area electronic diffraction(SAED),etc.(3) Through the analysis of the test results,the different influence mechanism have studied on the(Ba_0.3Sr_0.7)(Zn_1/3Nb_2/3)O₃ thin films growth of the sputtering power,the sputtering pressure,the annealing temperature,as well as the annealing time.