caa a22 4500 463213688 CHVBK 20180405153149.0 cr unu---uuuuu 170326e20071101xx s 000 0 eng 10.1007/s00339-007-4157-8 doi (NATIONALLICENCE)springer-10.1007/s00339-007-4157-8 Two-step sputtered ZnO piezoelectric films for film bulk acoustic resonators [Elektronische Daten] [Re-Ching Lin, Ying-Chung Chen, Kuo-Sheng Kao] This study investigates high-performance ZnO piezoelectric films used for thin film bulk acoustic resonators (TFBAR). The ZnO piezoelectric film was deposited on a Pt/Ti electrode using an RF magnetron sputter by a two-step method at room temperature. The Pt/Ti electrode was deposited by a DC sputtering system, on which, ZnO piezoelectric films were deposited in one step and in two steps to minimize roughness in the first step and produce the preferred orientation in the second. Both field-emission scanning electron microscopy (FESEM) and atom force microscopy (AFM) revealed that ZnO piezoelectric film deposited by two-step sputtering exhibited favorable characteristics, such as a rigidly precise surface structure with surface roughness of 7.37nm, even better than in one-step sputtering. Examining the ZnO thin film by X-ray diffraction (XRD) showed a much higher c-axis-preferring orientation than in one-step sputtering. The reflection coefficient of the resonator device was measured using an HP8720 network analyzer. The frequency response of the FBAR device exhibited a return loss of -25dB at a resonant frequency of 2212MHz with a high coupling coefficient of 6.7%. Springer-Verlag, 2007 Lin Re-Ching Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, R.O.C. aut Chen Ying-Chung Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, R.O.C. aut Kao Kuo-Sheng Department of Computer and Communication, Shu-Te University, 59 Hun Shan Rd., 82445, Yen Chau, Taiwan, R.O.C. aut Applied Physics A Springer-Verlag 89/2(2007-11-01), 475-479 0947-8396 89:2<475 2007 89 339 https://doi.org/10.1007/s00339-007-4157-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00339-007-4157-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Lin Re-Ching Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, R.O.C aut NATIONALLICENCE 700 1- Chen Ying-Chung Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, R.O.C aut NATIONALLICENCE 700 1- Kao Kuo-Sheng Department of Computer and Communication, Shu-Te University, 59 Hun Shan Rd., 82445, Yen Chau, Taiwan, R.O.C aut NATIONALLICENCE 773 0- Applied Physics A Springer-Verlag 89/2(2007-11-01), 475-479 0947-8396 89:2<475 2007 89 339 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer