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PREPARATION OF THE BRAGG REFLECTORS OF TUNEABLE THIN FILM BULK ACOUSTIC WAVE RESONATORS BY rf sputtering

International Conference on Superconducting Materials(ICSM 2006)

作者： Liang Qiao and Xiaofang Bi School of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China

In this work, MgO thin films were prepared by rf magnetron sputtering technique on two different substrates of Si (100) wafers and amorphous glasses. The influence of different deposition conditions such as substrate temperature, Ar pressure, film thicknesses on the crystal structure of MgO thin films were studied. BaTiO3 ferroelectric thin films were subsequently deposited on the MgO films. The XRD results showed that the orientation of MgO films was dependent greatly on the substrate temperature. A highly (100) oriented MgO thin films were obtained at the temperature of 800℃. The crystallographic texture has been deteriorated rapidly as the argon pressure decreased to 1.0 Pa. It has been also found that the film thickness has a great influence on the film orientation. High substrate temperature, high argon pressure and a certain thickness appear to be favorable for formation of a good texture for the MgO films. The structure and microstructure of the BaTiO3 films were various both with deposition conditions and with the crystallographic texture of the MgO. A highly (001) oriented ferroelectric BTO film was obtained on the MgO films with an optimized deposition conditions.

关键词： MgO films BTO films highly-orientation rf sputtering

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PREPARATION OF THE BRAGG REFLECTORS OF TUNEABLE THIN FILM BU...

High Potential Columnar Nanocrystalline AlN Films Deposited by rf Reactive Magnetron sputtering

2013全国压电和声波理论及器件技术研讨会

作者： Wei LUO Li-Jia WU Qiu-yun FU Xiang-yu CHEN Dong-xiang ZHOU School of Optics and Electronic Information Huazhong University of Science and Technology

Electrically tuneable thin film bulk acoustic wave resonators have drawn much attention for their advantages of high Q factors,integrable feature and small *** controlling of the thickness of the Bragg reflectors directly affects the Q-factor of the resonators with solidly mounted *** this paper,the preparation method to precisely control the thickness of the Bragg reflectors by rf sputtering has been *** structure of W/S1O alternated layers with different thicknesses was successfully prepared by rf sputtering *** film thicknesses showed good linearity over *** deposition rates of two layers under different annealing conditions were derived.

关键词： Thin film bulk acoustic wave resonator Solidly mounted resonator Bragg reflector rf sputtering

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Nano-Micro Letters 2012年第1期4卷 40-44页

作者： Chengzhang Han Da Chen Yaozhong Zhang Dong Xu Yijian Liu Eric Siu-Wai Kong Yafei Zhang Key Laboratory for Thin Film and Microfabrication of the Ministry of Education Research Institute of Micro/Nano Science and Technology Shanghai Jiao Tong University Department of Applied Physics College of Science Shandong University of Science and Technology

Columnar nanocrystalline aluminum nitride(cnc-AlN) thin films with(002) orientation and uniform texture have been deposited successfully on large silicon wafers by rf reactive magnetron *** the optimum sputtering parameters, the deposited cnc-AlN thin films show a c-axis preferred orientation with a crystallite size of about 28 nm and surface roughness(RMS) of about 1.29 nm. The cnc-AlN thin films were well transparent with an optical band gap about 4.8 e V, and the residual compressive stress and the defect density in the film have been revealed by Ramon spectroscopy. Moreover, piezoelectric performances of the cnc-AlN thin films executed effectively in a film bulk acoustic resonator structure.

关键词： Columnar film Aluminum nitride Piezoelectric effect rf sputtering Optical property

Characteristics of Sputter-deposited Gadolinia-doped Ceria Thin Films on Al2O3/SiO2/Si Systems

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Chinese Journal of Mechanical Engineering 2009年第3期22卷 384-389页

作者： LEE Chiapyng CHEN Yongsiou LIANG Hsuang Department of Chemical Engineering Taiwan University of Science and Technology Department of Materials Engineering Tatung University

Metal oxide films prepared by thin film technology have been reported for the potential applications on thin solid electrolyte layers for solid oxide fuel cells(SOFCs). Gadolinia-doped ceria(GDC) thin films and Al2O3 layers on SiO2/Si substrates are successively deposited by rf reactive magnetron sputtering from a cerium-gadolinium (90:10 at.%) alloy target and Al target in O2/Ar gas mixture and then perform post-thermal treatments at 300-700 ℃ and 900 ℃ for 2 h, respectively. Materials characteristics and chemical compositions of GDC films and Al2O3 layers are investigated by X-ray photoelectron spectroscopy(XPS), cross-sectional scanning electron microscopy(SEM), X-ray diffraction(XRD), and atomic force microscopy(AFM). Stoichiometric Al2O3 layers with polycrystalline structures are firstly prepared onto SiO2/Si substrates. A cubic fluorite structure with columnar crystallites of GDC films is successfully deposited on Al2O3/SiO2/Si systems. The chemical composition of 700 ℃-annealed GDC films is (Ce0.91Gd0.09)O1.94 and possesses a higher film density of 7.257 g/cm3. As a result, GDC thin films prepared by rf reactive magnetron sputtering and post-thermal treatments can be used as thin solid electrolyte layers for intermediate temperature SOFCs system as compared to the well-known yttria-stabilized zirconia(YSZ).

关键词： gadolinia-doped ceria(GDC) yttria-stabilized zirconia(YSZ) rf sputtering solid electrolytes solid oxide fuel cells

Nanostructural Features and Optical Performance of rf Magnetron Sputtered ZnO Thin Films

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Journal of Materials Science & Technology 2010年第11期26卷 986-990页

作者： A.K.Srivastava Praveen M.Arora S.K.Gupta B.R.Chakraborty S.Chandra S.Toyoda H.Bahadur Natonal Physical Laboratory Council of Scientific and Industrial Research Indian Institute of Technology Okayama University of Science

Zinc oxide （ZnO） thin films were grown on silicon substrate by rf （radio frequency） magnetron *** topography of these films exhibited a nanostructured granular appearance with the size of individual grains between 50 to 100 *** cross-sectional electron micrographs revealed columnar grains in the form of aggregated nanorods/wires with length of about 500 nm,similar to the thickness of these thin films of ZnO nucleated and grown vertically on the silicon *** resolution lattice scale imaging using high resolution transmission electron microscope （HRTEM） elucidated the single crystalline 1010 planes of hexagonal-ZnO constituting the columnar grains with the individual nanorod diameter between 3 and 4 *** photoluminescence measurements showed the prominent emission peak at around 460 nm for the blue band,normally attributed to intrinsic defects in particular interstitial zinc （Zn）.These films were further characterized by X-ray diffraction （XRD）,Fourier transform infrared spectroscopy （FTIR）,Raman spectroscopy and electron paramagnetic resonance （EPR） to evaluate various aspects on preferred growth orientations,band structures and vibrational modes originated in such fascinating nano-grained thin films of *** present investigations inferred that these films are advantageous in various potential applications for fabricating nano-scaled devices.

关键词： Electron microscopy Nanomaterials ZnO rf sputtering Photoluminescence Spectroscopy Electron paramagnetic resonance

Development of X-band accelerating structures for high gradients

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Chinese Physics C 2012年第7期36卷 639-647页

作者： S. Bini V. Chimenti A. Marcelli L. Palumbo B. Spataro V. A. Dolgashev S. Tantawi A. D. Yeremian Y. Higashi M. G. Grimaldi L. Romano F. Ruffino R. Parodi INFN-LNF Via E. Fermi 40 00044 Frascati (RM) Italy University of Rome Sapienza Dipartimento di EnergeticaVia A. Scarpa 14 00185 Rome Italy SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA KEK 1-1 Oho Tsukuba Ibaraki 305 Japan University of Catania Dipartimento di Fisica e Astronomia & MATIS-IMM-CNRVia S. Sofia 64 95123 Catania Italy INFN-Genova Via Dodecaneso 33 16146 Genova Italy

Short copper standing wave （SW） structures operating at an X-band frequency have been recently designed and manufactured at the Laboratori Nazionali di Frascati of the Istituto Nazionale di Fisica Nucleare （INFN） using the vacuum brazing technique. High power tests of the structures have been performed at the SLAC National Accelerator Laboratory. In this manuscript we report the results of these tests and the activity in progress to enhance the high gradient performance of the next generation of structures, particularly the technological characterization of high performance coatings obtained via molybdenum sputtering.

关键词： high-gradients soft X-ray FEL rf cavities for particle accelerators rf sputtering

Effects of Substrate Temperatures on the Structure and UV-shielding Properties of TiO_2-CeO_2 Films Deposited on Glass by Radio-frequency Magnetron sputtering

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Journal of Wuhan University of Technology(Materials Science) 2005年第4期20卷 7-9页

作者：赵青南 Key Laboratory of Silicate Materials Science and Engineering(Wuhan University of Technology) Ministry of Education Wuhan 430070 China

TiO2-CeO2 films were deposited on soda-lime glass substrates at varied substrate temperatures by rf magnetron sputtering using 40% molar TiO2-60% molar CeO2 ceramic target in Ar：O2=95：5 *** structure,surface composition,UV-visible spectra of the films were measured by scanning electron microscopy and X-ray diffraction,and X-ray photoelectron spectroscopy,*** experimental results show that the films are amorphous,there are only Ti^4＋ and Ce^4＋ on the surface of the films,the obtained TiO2-CeO2 films shou a good uniformity and high densification,and the films deposited on the glass can shield ultraviolet light without significant absorpition of visible light,the films deposited on substrates at room temperature and 220℃ absorb UV effectively.

关键词： rf sputtering TiO2-CeO2 films ultraviolet-shielding coating glass substrate temperatures

Cu_2ZnSnS_4 thin films prepared by sulfurizing different multilayer metal precursors

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Science China(Technological Sciences) 2009年第1期52卷 269-272页

作者： ZHANG Jun & SHAO LeXi School of Physical Science and Technology, Zhanjiang Normal University, Zhanjiang 524048, China School of Physical Science and Technology Zhanjiang Normal University

Cu2ZnSnS4 (CZTS) thin films were successfully fabricated on glass substrates by sulfurizing Cu-Sn-Zn multilayer precursors, which were deposited by ion beam sputtering and rf magnetron sputtering, respectively. The structural, electrical and optical properties of the prepared films under various processing conditions were investigated in detail. Results showed that the as-deposited CZTS thin films with the precursors by both ion beam sputtering and rf magnetron sputtering have a composition near stoichiometric. The crystallization of the samples, however, has a strong dependence on the atomic percent of constituents of the prepared CZTS films. A single phase stannite-type structure CZTS with a large absorption coefficient of 104/cm in the visible range could be obtained after sulfurization at 520℃ for 2 h. The samples relative to the rf magnetron sputtering showed a low resistivity of 0.073 ?cm and band gap energy of about 1.53 eV. The samples relative to the ion beam sputtering exhibited a resistivity of 0.36 Ωcm and the band gap energy is about 1.51 eV.

关键词： Cu_2ZnSnS_4 solar cell thin film ion beams sputtering rf sputtering

Optimization of piezoelectric MEMS process on Sr and La co-doped PZT thin films

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Journal of Advanced Dielectrics 2020年第4期10卷 6-12页

作者： M.Kathiresan Jain Jose E.Varadarajan R.Ramesh V.Natarajan M.K.Jayaraj T.Santhanakrishnan Naval Physical and Oceanographic Laboratory DRDO Kochi-682021India Research Innovation Centre DRDO Chennai-600113India Department of Physics Cochin University of Science and Technology Kochi-682022 India Combat Vehicle Research and Development Establishment DRDOChennai-600054India

Doped lead-zirconate-titanate(PZT)thin films are preferred for the development of micro-electro-mechanical systems(MEMS)-based acoustic sensors because of their inherent higher dielectric and piezoelectric *** process is used to develop such MEMS devices which is highly complex even for undoped PZT thin films;therefore,the problem is further cumbersome for doped PZT thin films due to the presence of added dopant elements and their associated *** paper presents patterning of strontium(Sr)and lanthanum(La)co-doped PZT thin film(PSLZT)deposited on platinized silicon substrate using wet and dry etching processes for fabricating a diaphragm structure with thickness of 15-25μm and diameter of 1.4-2 mm,suitable for acoustic sensing *** effects of various etching conditions have been studied and the results are *** is found that the dry etching is the most suited process for realizing the piezoelectric MEMS structure due to its higher etching *** appreciable etching rate of 260-270 nm/min with smooth vertical sidewalls is *** silicon diaphragm with patterned PSLZT thin film is found to retain more than 80%of its dielectric and piezoelectric coefficients and has a resonance of 1.43 MHz.

关键词： PZT etching rf sputtering Doped PZT Sr and La co-doping MEMS acoustic sensor