Frequency Characteristics of Li Doped ZnO Thin Film Resonator by Annealing Temperatures

열처리 온도에 따른 Li 도펀트 ZnO 박막형 공진기의 주파수 특성

  • Kim, Eung-Kwon (Department of Information and Communication, Sungkyunkwan University) ;
  • Kim, Young-Sung (Advanced Material Process of Information Technology, Sungkyunkwan University)
  • 김응권 (성균관대학교 전자전기 및 컴퓨터공학과) ;
  • 김용성 (성균관대학교 정보통신용 신기능성 소재 및 공정연구센터)
  • Published : 2006.09.01


In order to study the influence of post-annealing treatment on the frequency characteristics of the Li doped ZnO(Li:ZnO) FBAR(Film Bulk Acoustic Resonator) device, we investigated the material and electrical properties of Li:ZnO films in the annealing temperature range from 300 to $500^{\circ}C$. In our samples, as annealing temperature was increased, Li:ZnO films showed the improvement of high c-axis orientation and resistance value with relieved stress and low surface roughness. In addition to, the return loss in the frequency property of fabricated FBAR was improved by annealing treatment from 24.9 to 29.8dB. From experimental results, the optimum post-annealing temperature for FBAR is $500^{\circ}C$ and it can obtain excellent Li:ZnO FBAR performance with stronger c-axis orientation, smoother surface, relieved stress, and lower loss factor.


  1. G. A. Mohamed, E. M. Mohamed, and A. A. Elfadl, 'Optical Properties and Surface Morphology of Li-Doped ZnO Thin Films Deposited on Different Substrates by DC Magnetron Sputtering Method,' Physica. B, Condensed Matter, 308/310 949-53 (2001)
  2. K. K. Kim, H. Tampo, J. O. Song, T. Y. Seong, S. J. Park, J. M. Lee, S. W. Kim, S. Fijuta, and S. Niki, 'Effect of Rapid Thermal Annealing on Al Doped n-ZnO Films Grown by RF-Magnetron Sputtering(in Jpn.),' J. Appl. Phys., 44 [7A] 4776-79 (2005)
  3. M. K. Puchert, P. Y. Timbrell, and R. N. Lamb, 'Postdeposition Annealing of Radio Frequency Magnetron Sputtered ZnO Films,' J. Vac. Sci. Technol. A, 14 [4] 2220-30 (1996)
  4. M. Chen, Z. L. Pei, X. Wang, C. Sun, and L. S. Wen, 'Structural, Electrical, and Optical Properties of Transparent Conductive Oxide ZnO:Al Films Prepared by DC Magnetron Reactive Sputtering,' J. Vac. Sci. Technol. A, 19 [3] 963-70 (2001)
  5. B. D. Cullity and S. R. Stock, Elements of X-Ray Diffraction, pp. 123-31, Prentice Hall, 2001
  6. L. Mai, H. I. Song, L. M. Tuan, P. V. Su, and G. W. Yoon, 'A Comprehensive Investigation of Thermal Treatment Effects on Resonance Characteristics in FBAR Devices,' Microwave and Optical Technology Letters, 47 [5] 459-62 (2005)