本研究主要分析薄膜體聲波諧振器(thin film bulk acoustic wave resonator,FBAR)及濾波器頻寬改善之方法，方法是以兩階段沉積不同膜厚之壓電層於同一試片上，以達到不同諧振頻率之諧振器，進而完成改善濾波器頻寬之研究。本研究的FBAR元件分別採用背向蝕刻結構的FBAR元件，而FBAR的結構為在矽基板上，沉積下電極鉑、壓電層氮化鋁、上電極鋁。空腔採用ICP乾式蝕刻，蝕刻遮罩使用100nm的Al，而AlN壓電層是由射頻磁控濺鍍機沉積而成，所謂兩階段沉積是第一階段AlN壓電層沉積在基板溫度225℃，第二階段沉積為了配合舉離法製程，使AlN壓電層在室溫下成長。待製作完成，使用網路分析儀進行元件的頻率響應分析，根據量測結果藉由ADS模擬軟體萃取MBVD等效電路的元件數值。本研究製作出上電極為圓形、矩形與正方形的FBAR元件，量測結果其諧振頻率落在3.89～3.91間；兩階段沉積壓電層的正方形FBAR元件落在3.830 GHz，其中心頻率高於預期。根據量測結果運算求得元件輸入阻抗、阻抗相位與Q值，其穿透損耗太大且Q值不如預期。本研究製作FBAR元件良率太低且壓電層結晶品質不佳、上電極Al容易剝落、背向蝕刻空腔小時殘留之Si基板過厚，而空腔大時ICP蝕刻擊穿等問題。

Thin film bulk acoustic resonators(FBARs) are promising for communication applications higher than 2.4 GHz for its extremely low loss and compatible process with CMOS. In this thesis, we proposed a two-step-deposition method by using RF magnetron reactive sputter to fabricate the piezoelectric layers of FBARS with different thicknesses to provide different resonant frequencies, which are stringent for practical filter design with wide bandwidth. The structure of the FBARs from top to bottom were Al/AlN/Pt/ SiNx/Si with etched cavity in the back. A thin AlN film was deposited with heated substrate at 225℃ during the RF sputteirng process of first step. The second AlN thin film on the first thin film with covered photoresist for pattern defining was then re-sputtered without heating the substrate. The S-parameters measured by using GSG probe and network analyzer indicated that the resonant frequency of 3.90 GHz and anti-resonant frequency of 3.95 GHz were obtained for the FBAR of first-step deposition with estimated 1.02μm for the AlN thickness, and the resonant frequency of 3.83 GHz and anti-resonant frequency of 3.91 GHz for the FBAR with estimated 2.04μm for the AlN thickness combined of the first- and second-step deposition. The analysis of MBVD model showed that effective electromechanical coupling coefficient and quality factor for the first-step FBAR were 3.123% and 203, respectively, and 5.048% and 415 for the FBAR after the second-step deposition.

參考文獻
[1] 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," 成功大學電機工程學系學位論文, pp. 1-108, 2016.
[2] 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," 成功大學電機工程學系學位論文, pp. 1-71, 2006.
[3] Qualcomm, "IEEE802.11ac: The Next Evolution of Wi-Fi Standards," 2012.
[4] R. C. Ruby, P. Bradley, Y. Oshmyansky, A. Chien, and J. D. Larson, "Thin film bulk wave acoustic resonators (FBAR) for wireless applications," in Ultrasonics Symposium, 2001 IEEE, 2001, vol. 1, pp. 813-821: IEEE.
[5] S. Chauhan and P. Chawla, "Development of FBAR Filter for Wireless Applications," in National Conference “IAEISDISE, 2014, vol. 12, no. 13.
[6] 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 Ultrasonics, 2003 IEEE Symposium on, 2003, vol. 1, pp. 170-173: IEEE.
[7] 劉吉卿, "以兩階段濺鍍法沉積氧化鋅壓電薄膜於薄膜體聲波共振器之應用," 撰者, 2006.
[8] C. Fang, S. Lin, Y. Chin, P. Chen, H. Lin, and P. Chang, "5.4 GHz high-Q bandpass filter for wireless sensor network system," in Sensors, 2009 IEEE, 2009, pp. 1487-1491: IEEE.
[9] K. Lakin and J. Wang, "Acoustic bulk wave composite resonators," Applied Physics Letters, vol. 38, no. 3, pp. 125-127, 1981.
[10] G. Kline and K. Lakin, "1.0‐GHz thin‐film bulk acoustic wave resonators on GaAs," Applied Physics Letters, vol. 43, no. 8, pp. 750-751, 1983.
[11] C. Vale, J. Rosenbaum, S. Horwitz, S. Krishnaswamy, and R. Moore, "FBAR filters at GHz frequencies," in Frequency Control, 1990., Proceedings of the 44th Annual Symposium on, 1990, pp. 332-336: IEEE.
[12] D. Cushman, K. Lau, E. Garber, K. Mai, A. Oki, and K. Kobayashi, "SBAR filter monolithically integrated with HBT amplifier," in Ultrasonics Symposium, 1990. Proceedings., IEEE 1990, 1990, pp. 519-524: IEEE.
[13] R. C. Ruby and P. P. Merchant, "Tunable thin film acoustic resonators and method for making the same," ed: Google Patents, 1996.
[14] R. C. Ruby, "Post-fabrication tuning of acoustic resonators," ed: Google Patents, 1998.
[15] R. C. Ruby and P. P. Merchant, "Method of making tunable thin film acoustic resonators," ed: Google Patents, 1999.
[16] P. D. Bradley, J. D. Larson III, and R. C. Ruby, "Duplexer incorporating thin-film bulk acoustic resonators (FBARs)," ed: Google Patents, 2001.
[17] T. Nishihara, T. Yokoyama, T. Miyashita, and Y. Satoh, "High performance and miniature thin film bulk acoustic wave filters for 5 GHz," in Ultrasonics Symposium, 2002. Proceedings. 2002 IEEE, 2002, vol. 1, pp. 969-972: IEEE.
[18] B. P. Otis and J. M. Rabaey, "A 300µmW 1.9 GHz CMOS oscillator utilizing micromachined resonators," in Solid-State Circuits Conference, 2002. ESSCIRC 2002. Proceedings of the 28th European, 2002, pp. 151-154: IEEE.
[19] H. Yu, W. Pang, H. Zhang, and E. S. Kim, "Film bulk acoustic resonator at 4.4 GHz with ultra low temperature coefficient of resonant frequency," in Micro Electro Mechanical Systems, 2005. MEMS 2005. 18th IEEE International Conference on, 2005, pp. 28-31: IEEE.
[20] K. Nam, Y. Park, S. Hong, J. Pak, G. Park, and I. Song, "MEMS based bulk acoustic wave resonators for mobile applications," Integrated Ferroelectrics, vol. 77, no. 1, pp. 101-108, 2005.
[21] J. Y. Park, K. H. Lee, and S. J. Cheon, "Silicon bulk micromachined FBAR filter and duplexer for advanced handset applications," Microwave and Optical Technology Letters, vol. 49, no. 2, pp. 339-342, 2007.
[22] W. Pang, H. Zhang, S. Whangbo, and E. S. Kim, "High Q film bulk acoustic resonator from 2.4 to 5.1 GHz," in Micro Electro Mechanical Systems, 2004. 17th IEEE International Conference on.(MEMS), 2004, pp. 805-808: IEEE.
[23] H. Zhang and E. S. Kim, "Air-backed Al/ZnO/Al film bulk acoustic resonator without any support layer," in Frequency Control Symposium and PDA Exhibition, 2002. IEEE International, 2002, pp. 20-26: IEEE.
[24] M. Yim, D.-H. Kim, D. Chai, and G. Yoon, "Significant resonance characteristic improvements by combined use of thermal annealing and Co electrode in ZnO-based FBARs," Electronics Letters, vol. 39, no. 23, pp. 1638-1640, 2003.
[25] 魏炯權, "薄膜成形技術," 電子陶瓷材料, pp. 6-1~6-36, 2001.
[26] 吳朗, 電子陶瓷: 壓電陶瓷. 全欣, 1994.
[27] J. Rosenbaum, Bulk acoustic wave theory and devices. Artech House on Demand, 1988.
[28] G. Fuentes Iriarte, "AlN thin film electroacoustic devices," Acta Universitatis Upsaliensis, 2003.
[29] F. Gerfers, P. M. Kohlstadt, E. Ginsburg, M. Y. He, D. Samara-Rubio, and Y. Manoli, "Sputtered aln thin films for piezoelectric mems devices-fbar resonators and accelerometers," in Solid state circuits technologies: InTech, 2010.
[30] 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, 2010.
[31] E. Ruiz, S. Alvarez, and P. Alemany, "Electronic structure and properties of AlN," physical Review B, vol. 49, no. 11, p. 7115, 1994.
[32] P. Kuo, G. Auner, and Z. Wu, "Microstructure and thermal conductivity of epitaxial AlN thin films," Thin Solid Films, vol. 253, no. 1-2, pp. 223-227, 1994.
[33] J. Ruffner, P. Clem, B. Tuttle, D. Dimos, and D. Gonzales, "Effect of substrate composition on the piezoelectric response of reactively sputtered AlN thin films," Thin Solid Films, vol. 354, no. 1, pp. 256-261, 1999.
[34] C. Aardahl, J. Rogers, H. Yun, Y. Ono, D. Tweet, and S.-T. Hsu, "Electrical properties of AlN thin films deposited at low temperature on Si (100)," Thin Solid Films, vol. 346, no. 1-2, pp. 174-180, 1999.
[35] 周继承 and 石之杰, "AlN 电子薄膜材料的研究进展," 材料导报, vol. 21, no. 5, pp. 14-16, 2007.
[36] 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.
[37] 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.
[38] 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 Frequency Control Symposium and PDA Exhibition Jointly with the 17th European Frequency and Time Forum, 2003. Proceedings of the 2003 IEEE International, 2003, pp. 779-784: IEEE.
[39] W. G. Cady, "Piezoelectricity: an introduction to the theory and applications of electromechanical phenomena in crystals," 1946.
[40] H. Campanella, Acoustic wave and electromechanical resonators: concept to key applications. Artech House, 2010.
[41] S. Mahon and R. Aigner, "Bulk acoustic wave devices–why, how, and where they are going," in CS MANTECH Conference, 2007, pp. 15-18.
[42] 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.
[43] X. Hiao, Introduction to semiconductor manufacturing technology. Prentice Hall, 2000.
[44] 何菊生, 张萌, and 肖祁陵, "半导体外延层晶格失配度的计算," 南昌大學學報 (理科版), vol. 30, no. 1, pp. 63-67, 2006.
[45] 蔡政宏, "微機電製程應用於薄膜體聲波元件之研究," 撰者, 2006.
[46] 劉永宏, "氮化鋁薄膜體聲波共振器分析與研製," 成功大學電機工程學系學位論文, pp. 1-62, 2005.
[47] K. M. Lakin, "A review of thin-film resonator technology," IEEE Microwave Magazine, vol. 4, no. 4, pp. 61-67, 2003.
[48] 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.
[49] 蔡洵, 高杨, 黄振华, and 刘海涛, "薄膜体声波谐振器的测试与表征," 微纳电子技术, vol. 52, no. 10, pp. 660-665, 2015.
[50] 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.
[51] J. D. N. Cheeke, Fundamentals and applications of ultrasonic waves. CRC press, 2012.
[52] 陳信樺, "薄膜體聲波濾波器之製作及其特性優化," 撰者, 2009.
[53] Z. Zhang, Y. Lu, W. Pang, D. Zhang, and H. Zhang, "A high performance C-band FBAR filter," in Microwave Conference Proceedings (APMC), 2013 Asia-Pacific, 2013, pp. 923-926: IEEE.
[54] T. E. Kolding, "General accuracy considerations of microwave on-wafer silicon device measurements," in Microwave Symposium Digest. 2000 IEEE MTT-S International, 2000, vol. 3, pp. 1839-1842: IEEE.
[55] K. S. E. Ramadan and S. Evoy, "Low Temperature Reactive Sputtering of Thin Aluminum Nitride Films on Metallic Nanocomposites," PloS one, vol. 10, no. 7, p. e0133479, 2015.
[56] 呂奕璋, "以氮化鋁為壓電薄膜之高頻薄膜體聲波濾波器研製," 臺灣大學應用力學研究所學位論文, pp. 1-118, 2007.
[57] 宋人豪, "C 軸取向氮化鋁薄膜應用於鑽石表面聲波濾波器之研究," 成功大學材料科學及工程學系學位論文, pp. 1-81, 2004.
[58] 楊詠暉, "以反應式磁控濺鍍法低溫濺鍍氮化鋁薄膜之研究," 2004.
[59] 陳健興, "氮化鋁薄膜在鈮酸鋰基板上之表面聲波特性," 撰者, 2001.
[60] 黃靜茹, 黃興祿, 陳亮斌, and 謝光宇, "在底層電極上以常溫成長氮化鋁薄膜之研究," 材料科學與工程, vol. 34, no. 1, pp. 55-60, 2002.
[61] A. Ababneh, H. Kreher, and U. Schmid, "Etching behaviour of sputter-deposited aluminium nitride thin films in H3PO4 and KOH solutions," Microsystem Technologies, vol. 14, no. 4-5, pp. 567-573, 2008.
[62] I. Zubel and M. Kramkowska, "The effect of alcohol additives on etching characteristics in KOH solutions," Sensors and Actuators A: Physical, vol. 101, no. 3, pp. 255-261, 2002.
[63] 羅正忠 and 張鼎張, "半導體製程技術導論," 台灣培生教育出版股份有限公司, 民國 98 年, 2002.