吳政忠臺灣大學：應用力學研究所武良臣Wu, Liang-ChenLiang-ChenWu2007-11-292018-06-292007-11-292018-06-292004http://ntur.lib.ntu.edu.tw//handle/246246/62508In recent years, there are studies aimed at phononic crystals, both experimentally and theoretically. However, the smallest scale of the phononic structures considered is in the millimeter scale and the frequency is limited in the MHz range. For the purpose toward the applications of phononic crystals to micro electromechanical system (MEMS) related components, it is necessary to reduce the lattice size to micrometer or even in nanometer scale. In order to achieve the objective, the band gap width of surface waves of micrometer scale phononic crystals has to be measured and compared with the theoretical calculation such as plane wave expansion (PWE) method. Moreover, for further integrating with the complementary metal-oxide semiconductor (CMOS) processing techniques, silicon is chosen to be the base material of the two dimensional phononic crystals in this thesis. Therefore, a high frequency wide-band surface acoustic wave (SAW) filter on a silicon substrate is needed to carry out this band gap measurement. The general used wide-band SAW filter is the slanted finger interdigital transducer (SFIT). Nevertheless, since the silicon is not piezoelectric materials, the layered structure SFIT/ZnO/silicon is thus considered in this thesis. For the layered structure, the dispersive relation is calculated by the effective permittivity approach, and the frequency response of layered SFIT can then be simulated by the coupling-of-modes (COM) model. Since the actual parameters of a layered SFIT are different slightly from the designed parameters, the simulated frequency response has to be modified. Results show that the modified simulations are in good agreement with experimental frequency responses. Finally, the band gap width and frequency range of 2-D air/silicon phononic crystals in micrometer-scale are successfully measured by the layered SFIT, and this experimental measurement agrees with the theoretical prediction by PWE method.Acknowledgements I Abstract II Lists of Notations III Table of Contents VIII List of Figures X List of Tables XII Chapter 1 Introduction 1 1-1 Motivation 1 1-2 Literature Review 2 1-3 Contents of the Chapters 3 Chapter 2 Analysis of Layered SFIT SAW Filter 6 2-1 Characteristics of SAW on Layered Structure 6 2-1.1 Effective Permittivity 6 2-1.2 Electromagnetic Coupling Coefficient 10 2-2 Analysis of COM Parameters on Layered Structure 11 2-2.1 Phase Velocity Shift 12 2-2.2 Reflection Coefficient 13 2-2.3 Transduction Coefficient 15 2-2.4 Thin Film Finger Capacitance and Resistance 15 2-2.5 Propagation Loss 16 2-3 Simulation of a Layered SFIT SAW Filter 17 2-3.1 Simulation Method of SFIT 17 2-3.2 Advantages of Layered SFIT 20 2-3.3 SFIT/ZnO/Silicon Layered SAW Filter 21 Chapter 3 Simulation of 2-D Phononic Crystal and Experimental Design 30 3-1 Theory of 2-D Phononic Crystals 30 3-1.1 Equation of Motion 30 3-1.2 Mass Density and Elastic constants 31 3-1.3 Displacement Vector 33 3-1.4 Surface and Bulk Waves in 2D Phononic Crystals 33 3-2 Simulation of 2-D Air/Si Phononic Crystal 37 3-2.1 Air/Silicon Square Lattice 37 3-2.2 The Dispersion Relation of 2-D Air/Si Phononic Crystal 38 3-3 Experimental Design and Frame of This Study 39 Chapter 4 Fabrications and Experimental Results 50 4-1 Growth of ZnO Thin Film on Silicon Substrate 50 4-1.1 Deposition of ZnO Thin Film 50 4-1.2 Analysis of Thin Film properties 51 4-2 Fabrication of Layered SFIT and 2-D Phononic Crystal 52 4-2.1 Fabrication Process of IDT/ZnO/Silicon Layered SFIT 52 4-2.2 Fabrication Processes of 2-D Air/Silicon Phononic Crystal 54 4-3 Experimental Results of the Layered SFIT 56 4-3.1 Time Gating Approach 56 4-3.2 Comparisons of simulation and experimental results 57 4-4 2-D Air/Si Phononic Crystal Band Gap Measurement 59 Chapter 5 Conclusions and Future Works 81 5-1 Conclusions of this thesis 81 5-2 Future works 81 Appendix 83 References 851958011 bytesapplication/pdfen-US頻溝表面波表面聲波濾波器層狀寬頻表面聲波濾波器聲子晶體SFITphononic crystalslayered SFITSAWband gapthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/62508/1/ntu-93-R91543028-1.pdf