本論文主要分析與研製薄膜體聲波諧振器(thin Film Bulk Acoustic wave Resonator, FBAR)及濾波器，分別採用背向空腔架構的FBAR元件和階梯式濾波器，FBAR的結構為在矽基板上以鉑作為下電極、氮化鋁為壓電層、鋁為上電極。本研究採用反應式射頻磁控濺鍍沉積高C軸優選取向的氮化鋁薄膜，以具備壓電特性、於元件內部激發縱向聲波，並經由適當設計與配置，最終達到濾波的效果。
實驗為探討質量負載效應對FBAR元件的影響與製作並分析二階FBAR濾波器，發現較薄壓電層之實作FBAR元件與較厚壓電層元件相比，前者具有更高的諧振頻率與較大的頻率對上電極厚度變化量，而後者則有更佳的諧振特性、機電耦合係數、Q值及FOM，當上電極厚度增加時，諧振頻率、機電耦合係數及頻率飄移程度則隨之下降。利用ADS模擬軟體萃取修正後之MBVD等效電路模型各項參數，可使模擬與量測結果相當接近，其中較厚壓電層之各項電路元件值的變化與上電極具有規律性，適合用於模擬、設計濾波器與預測其特性。
在FBAR濾波器特性分析方面，發現採用共同壓電層、空腔結構仍不會破壞其濾波特性且與模擬結果相近，而當濾波器中兩FBAR元件間距過近時，有穿透損耗增加的情況發生。

In this thesis, FBAR elements and filters of backside etched structure for 5G communication have been proposed and fabricated. The high C-axis-oriented piezoelectric layer of AlN with thickness of 1.2 μm was fabricated by using reactive RF magnetron sputtering. For the realization of FBAR filters, FBARs with varied resonant frequencies due to different thicknesses of top electrodes were made.
When the thickness of the top electrode deposited on the FBAR elements increased from 100 nm to 250 nm, its resonant and anti-resonant frequency were between 2.9 GHz and 2.6 GHz. The effective electromechanical coupling coefficient was between 3.23% and 2.73%, and the insertion loss was approximately 7dB. An equivalent circuit including the MBVD model was used to fit the measurement and could be further to derive quality factor of FBARs. The results show that the Q factors for resonant and anti-resonant frequencies are about 1000 and 550.
For the fabrication of filters, a second order ladder-type structure were used, which consisted of two FBAR elements separated in 100 um while sharing the same piezoelectric layer and air cavity. The thickness of top electrodes were 100 nm and 115 nm for the FBAR elements, respectively. The final result showed that the center frequency of the FBAR filter was 2.882 GHz, and 40MHz for bandwidth and 7.569 dB for insertion loss.

[1] wikipedia. "5G." https://zh.wikipedia.org/wiki/5G (accessed December 8, 2021).
[2] Y. Liu, Y. Cai, Y. Zhang, A. Tovstopyat, S. Liu, and C. Sun, "Materials, Design, and Characteristics of Bulk Acoustic Wave Resonator: A Review," Micromachines, vol. 11, no. 7, p. 630, 2020.
[3] Z. Zhang, Y. Lu, W. Pang, D. Zhang, and H. Zhang, "A high performance C-band FBAR filter," in 2013 Asia-Pacific Microwave Conference Proceedings (APMC), 2013: IEEE, pp. 923-926.
[4] N. Ashraf, Y. Mesbah, A. Emad, and H. Mostafa, "Enabling the 5G: Modelling and Design of High Q Film Bulk Acoustic Wave Resonator (FBAR) for High Frequency Applications," in 2020 IEEE International Symposium on Circuits and Systems (ISCAS), 2020: IEEE, pp. 1-4.
[5] R. Aigner, "High performance RF-filters suitable for above IC integration: film bulk-acoustic-resonators (FBAR) on silicon," in Proceedings of the IEEE 2003 Custom Integrated Circuits Conference, 2003: IEEE, pp. 141-146.
[6] Y. Zou et al., "Dual-mode thin film bulk acoustic wave resonator and filter," Journal of Applied Physics, vol. 128, no. 19, p. 194503, 2020.
[7] M. Barekatain, "Review of Radio Frequency Front-end Filters Based on Film Bulk Acoustic Resonators (FBAR)," 2018.
[8] R. C. Ruby, P. Bradley, Y. Oshmyansky, A. Chien, and J. Larson, "Thin film bulk wave acoustic resonators (FBAR) for wireless applications," in 2001 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No. 01CH37263), 2001, vol. 1: IEEE, pp. 813-821.
[9] S. Chen, Q. Yin, C. Hu, and Z. Huang, "Design and Optimization of FBAR Filter Using Acoustic-Electromagnetic Coupling Model and MBVD Model," in 2020 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO), 2020: IEEE, pp. 1-3.
[10] C. Men and C. Lin, "A comparison of pulsed-laser-deposited and ion-beam-enhanced-deposited AlN thin films for SOI application," Materials Science and Engineering: B, vol. 133, no. 1-3, pp. 124-128, 2006.
[11] H. Cheng, Y. Sun, and P. Hing, "Microstructure evolution of AlN films deposited under various pressures by RF reactive sputtering," Surface and coatings technology, vol. 166, no. 2-3, pp. 231-236, 2003.
[12] I. Oliveira, K. Grigorov, H. Maciel, M. Massi, and C. Otani, "High textured AlN thin films grown by RF magnetron sputtering; composition, structure, morphology and hardness," Vacuum, vol. 75, no. 4, pp. 331-338, 2004.
[13] C. Han et al., "High potential columnar nanocrystalline AlN films deposited by RF reactive magnetron sputtering," Nano-Micro Letters, vol. 4, no. 1, pp. 40-44, 2012.
[14] K.-W. Tay, C.-L. Huang, and L. Wu, "Highly c-axis oriented thin AlN films deposited on gold seed layer for FBAR devices," Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, vol. 23, no. 4, pp. 1474-1479, 2005.
[15] J.-P. Jung, J.-B. Lee, M.-H. Lee, and J.-S. Park, "Experimental and theoretical investigation on the relationship between AlN properties and AlN-based FBAR characteristics," in IEEE International Frequency Control Symposium and PDA Exhibition Jointly with the 17th European Frequency and Time Forum, 2003. Proceedings of the 2003, 2003: IEEE, pp. 779-784.
[16] R. Aigner, G. Fattinger, M. Schaefer, K. Karnati, R. Rothemund, and F. Dumont, "BAW filters for 5G bands," in 2018 IEEE International Electron Devices Meeting (IEDM), 2018: IEEE, pp. 14.5. 1-14.5. 4.
[17] A. Link, E. Schmidhammer, H. Heinze, M. Mayer, B. Bader, and R. Weigel, "Appropriate methods to suppress spurious fbar modes in volume production," in 2006 IEEE MTT-S International Microwave Symposium Digest, 2006: IEEE, pp. 394-397.
[18] D. Rosén, J. Bjurstrom, and I. Katardjiev, "Suppression of spurious lateral modes in thickness-excited FBAR resonators," IEEE transactions on ultrasonics, ferroelectrics, and frequency control, vol. 52, no. 7, pp. 1189-1192, 2005.
[19] J. F. Rosenbaum, Bulk acoustic wave theory and devices. Artech House Acoustics Library, 1988.
[20] S. Katzir, "The discovery of the piezoelectric effect," in the Beginnings of Piezoelectricity: Springer, 2006, pp. 15-64.
[21] P. Dineva, D. Gross, R. Müller, and T. Rangelov, "Piezoelectric materials," in Dynamic fracture of piezoelectric materials: Springer, 2014, pp. 7-32.
[22] R. G. Polcawich and J. S. Pulskamp, "Additive processes for piezoelectric materials: Piezoelectric MEMS," in MEMS materials and Processes Handbook: Springer, 2011, pp. 273-353.
[23] 吳朗, 電子陶瓷: 壓電陶瓷. 全欣, 1994.
[24] A. I. S. 176-, "IEEE standard on piezoelectricity," ed: The Institute of Electrical and Electronics Engineers, Inc. New York, 1987.
[25] G. Fuentes Iriarte, "AlN thin film electroacoustic devices," Acta Universitatis Upsaliensis, 2003.
[26] F. Gerfers et al., "Sputtered AlN thin films for piezoelectric MEMS devices-FBAR resonators and accelerometers," Solid state circuits technologies, p. 333, 2010.
[27] J. Erhart, P. Půlpán, and M. Pustka, Piezoelectric ceramic resonators. Springer, 2017.
[28] L. Qin, Q. Chen, H. Cheng, and Q.-M. Wang, "Analytical study of dual-mode thin film bulk acoustic resonators (FBARs) based on ZnO and AlN films with tilted c-axis orientation," IEEE transactions on ultrasonics, ferroelectrics, and frequency control, vol. 57, no. 8, pp. 1840-1853, 2010.
[29] K.-W. Tay, C.-L. Huang, and L. Wu, "Influence of piezoelectric film and electrode materials on film bulk acoustic-wave resonator characteristics," Japanese journal of applied physics, vol. 43, no. 3R, p. 1122, 2004.
[30] A. Khan, Z. Abas, H. S. Kim, and I.-K. Oh, "Piezoelectric thin films: an integrated review of transducers and energy harvesting," Smart Materials and Structures, vol. 25, no. 5, p. 053002, 2016.
[31] X.-H. Xu, H.-S. Wu, C.-J. Zhang, and Z.-H. Jin, "Morphological properties of AlN piezoelectric thin films deposited by DC reactive magnetron sputtering," Thin solid films, vol. 388, no. 1-2, pp. 62-67, 2001.
[32] G. F. Iriarte, J. Rodríguez, and F. Calle, "Synthesis of c-axis oriented AlN thin films on different substrates: A review," Materials Research Bulletin, vol. 45, no. 9, pp. 1039-1045, 2010.
[33] P. Muralt, "AlN thin film processing and basic properties," in Piezoelectric MEMS resonators: Springer, 2017, pp. 3-37.
[34] S. Trolier-McKinstry and P. Muralt, "Thin film piezoelectrics for MEMS," Journal of Electroceramics, vol. 12, no. 1, pp. 7-17, 2004.
[35] S. G.-C. J. Olivares, M. Clement, A. Sanz-Hervás, L. Vergara, J. Sangrador, E. Iborra, "Combined assessment of piezoelectric AlN films using X-ray diffraction, infrared absorption and atomic force microscopy," Diamond and Related Materials, vol. 16, no. 4-7, pp. 1421-1424, 2007. [Online]. Available: https://www.sciencedirect.com/science/article/pii/S0925963506004651.
[36] T. Nishihara, T. Yokoyama, T. Miyashita, and Y. Satoh, "High performance and miniature thin film bulk acoustic wave filters for 5 GHz," in 2002 IEEE Ultrasonics Symposium, 2002. Proceedings., 2002, vol. 1: IEEE, pp. 969-972.
[37] A. Ababneh, U. Schmid, J. Hernando, J. Sánchez-Rojas, and H. Seidel, "The influence of sputter deposition parameters on piezoelectric and mechanical properties of AlN thin films," Materials Science and Engineering: B, vol. 172, no. 3, pp. 253-258, 2010.
[38] C. C. Ruppel, "Acoustic wave filter technology–A review," IEEE transactions on ultrasonics, ferroelectrics, and frequency control, vol. 64, no. 9, pp. 1390-1400, 2017.
[39] S. Mahon and R. Aigner, "Bulk acoustic wave devices–why, how, and where they are going," in CS Mantech Conference, 2007, pp. 15-18.
[40] H. Campanella, Acoustic wave and electromechanical resonators: concept to key applications. Artech House, 2010.
[41] C. P. Wen, "Coplanar waveguide: A surface strip transmission line suitable for nonreciprocal gyromagnetic device applications," IEEE Transactions on Microwave Theory and Techniques, vol. 17, no. 12, pp. 1087-1090, 1969.
[42] T. Chao, Introduction to semiconductor manufacturing technology. SPIE PRESS, 2001.
[43] Y. Gao, W.-j. He, J.-r. Li, and Z.-h. Huang, "FBAR-on-diaphragm type electro-acoustic resonant micro-accelerometer: A theoretical study," Microsystem Technologies, vol. 22, no. 7, pp. 1575-1583, 2016.
[44] N. Nor, Y. Jing, and N. Khalid, "Characteristics of film bulk acoustic wave resonator using different electrode materials," in AIP Conference Proceedings, 2021, vol. 2347, no. 1: AIP Publishing LLC, p. 020144.
[45] M. Hara, J. Kuypers, T. Abe, and M. Esashi, "Surface micromachined AlN thin film 2 GHz resonator for CMOS integration," Sensors and Actuators A: Physical, vol. 117, no. 2, pp. 211-216, 2005.
[46] M.-A. Dubois and P. Muralt, "Properties of aluminum nitride thin films for piezoelectric transducers and microwave filter applications," Applied Physics Letters, vol. 74, no. 20, pp. 3032-3034, 1999.
[47] M.-A. Dubois and P. Muralt, "Stress and piezoelectric properties of aluminum nitride thin films deposited onto metal electrodes by pulsed direct current reactive sputtering," Journal of Applied Physics, vol. 89, no. 11, pp. 6389-6395, 2001.
[48] M. Terzieva, "Overview of bulk acoustic wave technology and its applications," in National conference with international participation “ELECTRONICA 2016”, 2016, pp. 86-91.
[49] K. M. Lakin, "Modeling of thin film resonators and filters," in 1992 IEEE MTT-S Microwave Symposium Digest, 1992: IEEE, pp. 149-152.
[50] I. S. Uzunov, M. D. Terzieva, B. M. Nikolova, and D. G. Gaydazhiev, "Extraction of modified butterworth—Van Dyke model of FBAR based on FEM analysis," in 2017 XXVI International Scientific Conference Electronics (ET), 2017: IEEE, pp. 1-4.
[51] M. Moreira, J. Bjurström, I. Katardjev, and V. Yantchev, "Aluminum scandium nitride thin-film bulk acoustic resonators for wide band applications," Vacuum, vol. 86, no. 1, pp. 23-26, 2011.
[52] N. Nor et al., "The influence of design parameters on the performance of FBAR in 15–19 GHz," in AIP Conference Proceedings, 2018, vol. 2045, no. 1: AIP Publishing LLC, p. 020088.
[53] Y. Zhang and D. Chen, Multilayer Integrated Film Bulk Acoustic Resonators. Springer, 2013, pp. 31-50.
[54] C.-M. Yang, K. Uehara, S.-K. Kim, S. Kameda, H. Nakase, and K. Tsubouchi, "Highly c-axis-oriented AlN film using MOCVD for 5GHz-band FBAR filter," in IEEE Symposium on Ultrasonics, 2003, 2003, vol. 1: IEEE, pp. 170-173.
[55] R. Ruby, "11E-2 Review and comparison of bulk acoustic wave FBAR, SMR Technology," in 2007 IEEE Ultrasonics Symposium Proceedings, 2007: IEEE, pp. 1029-1040.
[56] H. Zhang and E. S. Kim, "Micromachined acoustic resonant mass sensor," Journal of Microelectromechanical Systems, vol. 14, no. 4, pp. 699-706, 2005.
[57] H. Campanella et al., "Localized-mass detection based on thin-film bulk acoustic wave resonators (FBAR): Area and mass location aspects," Sensors and Actuators A: Physical, vol. 142, no. 1, pp. 322-328, 2008.
[58] H. Campanella, E. Martincic, P. Nouet, A. Uranga, and J. Esteve, "Analytical and finite-element modeling of localized-mass sensitivity of thin-film bulk acoustic-wave resonators (FBAR)," IEEE Sensors Journal, vol. 9, no. 8, pp. 892-901, 2009.
[59] H. Campanella, "Tunable FBARs: Frequency tuning mechanisms," in The 40th European Microwave Conference, 2010: IEEE, pp. 795-798.
[60] Q. Su, P. Kirby, E. Komuro, and R. Whatmore, "Edge supported ZnO thin film bulk acoustic wave resonators and filter design," in Proceedings of the 2000 IEEE/EIA International Frequency Control Symposium and Exhibition (Cat. No. 00CH37052), 2000: IEEE, pp. 434-440.
[61] S. Enjamuri, A. Amsanpally, and K. J. Raju, "Optimization and analysis of piezoelectric and electrode materials' thickness effects on the performance of film bulk acoustic resonator," in 2012 1st International Symposium on Physics and Technology of Sensors (ISPTS-1), 2012: IEEE, pp. 185-188.
[62] B. Qi, Y. Lu, D. Hua, and C. Cai, "Resonate frequency research on material characteristics of FBAR temperature sensor," in 2017 IEEE 9th International Conference on Communication Software and Networks (ICCSN), 2017: IEEE, pp. 344-348.
[63] 劉永宏, "氮化鋁薄膜體聲波共振器分析與研製," 2005.
[64] 林哲榆, "以非晶質氮化鋁為支撐層之薄膜型塊體聲波共振器的研究," 2006.
[65] 沈昱翔, "高頻通訊之氮化鋁薄膜體聲波諧振器及濾波器的研製與分析," 2016.
[66] K. Lakin, J. Belsick, J. McDonald, and K. McCarron, "High performance stacked crystal filters for GPS and wide bandwidth applications," in 2001 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No. 01CH37263), 2001, vol. 1: IEEE, pp. 833-838.
[67] J. D. N. Cheeke, Fundamentals and applications of ultrasonic waves. CRC press, 2010.
[68] N. I. M. Nor, K. Shah, J. Singh, and Z. Sauli, "Design and analysis of wideband ladder-type film bulk acoustic wave resonator filters in Ku-band," Active and Passive Electronic Components, vol. 2013, 2013.
[69] M. Handtmann, S. Marksteiner, J. Kaitila, and R. Aigner, "Bulk acoustic wave filters for GPS with extreme stopband attenuation," in 2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No. 04CH37535), 2004, vol. 1: IEEE, pp. 371-374.
[70] Y. Gao, S.-w. Wen, C. Han, and D.-p. Zhang, "A method determining order of BAW ladder-type filter," in Emerging Imaging and Sensing Technologies for Security and Defence III; and Unmanned Sensors, Systems, and Countermeasures, 2018, vol. 10799: International Society for Optics and Photonics, p. 107990L.
[71] S. A. Sis, "Ferroelectric-on-Silicon Switchable Bulk Acoustic Wave Resonators and Filters for RF Applications," 2014.
[72] Q.-X. Su, P. Kirby, E. Komuro, M. Imura, Q. Zhang, and R. Whatmore, "Thin-film bulk acoustic resonators and filters using ZnO and lead-zirconium-titanate thin films," IEEE Transactions on Microwave Theory and Techniques, vol. 49, no. 4, pp. 769-778, 2001.
[73] J. Y. Park et al., "Micromachined FBAR RF filters for advanced handset applications," in TRANSDUCERS'03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No. 03TH8664), 2003, vol. 1: IEEE, pp. 911-914.
[74] K.-W. Kim, M.-G. Gu, J.-G. Yook, and H.-K. Park, "Resonator size effects on the TFBAR ladder filter performance," IEEE microwave and wireless components letters, vol. 13, no. 8, pp. 335-337, 2003.
[75] G. Iriarte, J. Rodriguez, and F. Calle, "Effect of substrate–target distance and sputtering pressure in the synthesis of AlN thin films," Microsystem technologies, vol. 17, no. 3, pp. 381-386, 2011.
[76] M. Arif, M. Sauer, A. Foelske-Schmitz, and C. Eisenmenger-Sittner, "Characterization of aluminum and titanium nitride films prepared by reactive sputtering under different poisoning conditions of target," Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, vol. 35, no. 6, p. 061507, 2017.
[77] W. Lang, "Silicon microstructuring technology," Materials Science and Engineering: R: Reports, vol. 17, no. 1, pp. 1-55, 1996.
[78] K. Biswas and S. Kal, "Etch characteristics of KOH, TMAH and dual doped TMAH for bulk micromachining of silicon," Microelectronics journal, vol. 37, no. 6, pp. 519-525, 2006.
[79] K. Tokoro, D. Uchikawa, M. Shikida, and K. Sato, "Anisotropic etching properties of silicon in KOH and TMAH solutions," in MHA'98. Proceedings of the 1998 International Symposium on Micromechatronics and Human Science.-Creation of New Industry-(Cat. No. 98TH8388), 1998: IEEE, pp. 65-70.
[80] F. Engelmark, G. Fucntes, I. Katardjiev, A. Harsta, U. Smith, and S. Berg, "Synthesis of highly oriented piezoelectric AlN films by reactive sputter deposition," Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, vol. 18, no. 4, pp. 1609-1612, 2000.
[81] M. Ohring, Materials science of thin films. Elsevier, 2001.
[82] F. Martin, P. Muralt, M.-A. Dubois, and A. Pezous, "Thickness dependence of the properties of highly c-axis textured AlN thin films," Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, vol. 22, no. 2, pp. 361-365, 2004.
[83] T. Yokoyama et al., "New electrode material for low-loss and high-Q FBAR filters," in IEEE Ultrasonics Symposium, 2004, 2004, vol. 1: IEEE, pp. 429-432.
[84] T. Yokoyama, Y. Iwazaki, Y. Onda, T. Nishihara, Y. Sasajima, and M. Ueda, "Highly piezoelectric co-doped AlN thin films for wideband FBAR applications," IEEE transactions on ultrasonics, ferroelectrics, and frequency control, vol. 62, no. 6, pp. 1007-1015, 2015.
[85] L. Khine, L. Y. Wong, J. B. Soon, and M. L. J. Tsai, "FBAR resonators with sufficient high Q for RF filter implementation," in Advanced Materials Research, 2011, vol. 254: Trans Tech Publ, pp. 70-73.
[86] H. Campanella, A. Uranga, P. Nouet, P. De Paco, N. Barniol, and J. Esteve, "Instantaneous De-embedding of the on-wafer equivalent-circuit parameters of acoustic resonator (FBAR) for Integrated Circuit Applications," in Proceedings of the 20th annual conference on Integrated circuits and systems design, 2007, pp. 212-217.
[87] G. Pillai, A. A. Zope, J. M.-L. Tsai, and S.-S. Li, "Design and optimization of SHF composite FBAR resonators," IEEE transactions on ultrasonics, ferroelectrics, and frequency control, vol. 64, no. 12, pp. 1864-1873, 2017.
[88] Y. Zhang, J. Luo, A. J. Flewitt, Z. Cai, and X. Zhao, "Film bulk acoustic resonators (FBARs) as biosensors: A review," Biosensors and Bioelectronics, vol. 116, pp. 1-15, 2018.
[89] H. Zhang, M. S. Marma, E. S. Kim, C. E. McKenna, and M. E. Thompson, "Implantable resonant mass sensor for liquid biochemical sensing," in 17th IEEE International Conference on Micro Electro Mechanical Systems. Maastricht MEMS 2004 Technical Digest, 2004: IEEE, pp. 347-350.