Comprehensive characterization of ZnO thin films for surface acoustic wave applications

Abstract

This paper presents a comprehensive characterization of a very smooth, c-axis oriented, highly piezoelectric and electrically resistive 2.5 µm-thick ZnO thin film deposited by a radio frequency (RF) magnetron sputtering system on SiO2/Si substrate. Thin film properties such as surface roughness, crystallography, stoichiometry, and electrical resistivity are measured. Two-port surface acoustic wave (SAW) devices with bidirectional interdigital transducer (IDT) periods of 16 µm, 20 µm and 24 µm are fabricated on top of the ZnO thin film. A detailed finite element analysis (FEA) of the thin film is elaborated by varying ZnO thickness and IDT configuration. FEA results shows that acoustic wave velocities and resonance frequencies of the SAW devices are decreasing together with increasing ZnO thickness. Frequency response of the fabricated SAW devices are measured with a vector network analyzer (VNA) and compared to FEA results. First two wave modes, namely the Rayleigh and Sezawa waves, of the fabricated SAW devices on the ZnO thin films are interrogated. Resonance frequencies of the SAW devices with wavelengths of 16 µm, 20 µm, and 24 µm are measured as 204.8 MHz, 176.3 MHz, and 155.3 MHz for the Rayleigh mode, 335.9 MHz, 275.3 MHz, and 235.1 MHz for the Sezawa mode, respectively. In addition, omnidirectional wave propagation of ZnO thin film is shown with 45° rotated IDTs. Overall, experimental results are in good agreement with simulation results, demonstrating ZnO thin film fabrication is successfully carried out, and FEA is an appropriate method for modeling SAW devices on thin films.

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References

  1. 1.

    J.L. Gomez, O. Tigli, Zinc oxide nanostructures: from growth to application. J. Mater. Sci. 48(2), 612–624 (2013)

    Article  Google Scholar 

  2. 2.

    U. Ozgur, D. Hofstetter, H. Morkoc, ZnO devices and applications: a review of current status and future prospects. Proc. IEEE 98(7), 1255–1268 (2010)

    Article  Google Scholar 

  3. 3.

    T. Minami, H. Nanto, S. Takata, Highly conductive and transparent zinc oxide films prepared by rf magnetron sputtering under an applied external magnetic field. Appl. Phys. Lett. 41(10), 958–960 (1982)

    Article  Google Scholar 

  4. 4.

    R. Singh, M. Kumar, S. Chandra, Growth and characterization of high resistivity c-axis oriented ZnO films on different substrates by RF magnetron sputtering for MEMS applications. J. Mater. Sci. 42(12), 4675–4683 (2007)

    Article  Google Scholar 

  5. 5.

    L. Znaidi, Sol–gel-deposited ZnO thin films: a review. Mater. Sci. Eng., B 174(1-3), 18–30 (2010)

    Article  Google Scholar 

  6. 6.

    D. Zaouk et al., Piezoelectric zinc oxide by electrostatic spray pyrolysis. Microelectron. J. 37(11), 1276–1279 (2006)

    Article  Google Scholar 

  7. 7.

    N.W. Emanetoglu et al., Epitaxial ZnO piezoelectric thin films for saw filters. Mater. Sci. Semicond. Process. 2(3), 247–252 (1999)

    Article  Google Scholar 

  8. 8.

    R. Serhane et al., Pulsed laser deposition of piezoelectric ZnO thin films for bulk acoustic wave devices. Appl. Surf. Sci. 288, 572–578 (2014)

    Article  Google Scholar 

  9. 9.

    O. Tigli, M.E. Zaghloul, Temperature stability analysis of CMOS-saw devices by embedded heater design. IEEE Trans. Device Mater. Reliabil. 8(4), 705–713 (2008)

    Article  Google Scholar 

  10. 10.

    M.J. Madou, Fundamentals of Microfabrication and Nanotechnology, Three-Volume Set (CRC Press, Boca Raton, 2011)

    Google Scholar 

  11. 11.

    Q.J. Wang et al., Gigahertz surface acoustic wave generation on ZnO thin films deposited by radio frequency magnetron sputtering on III-V semiconductor substrates. J. Vac. Sci. Technol., B 26(6), 1848–1851 (2008)

    Article  Google Scholar 

  12. 12.

    H. Jin et al., Flexible surface acoustic wave resonators built on disposable plastic film for electronics and lab-on-a-chip applications. Sci. Rep. 3, 2140 (2013)

    Article  Google Scholar 

  13. 13.

    A. Talbi et al., ZnO/quartz structure potentiality for surface acoustic wave pressure sensor. Sens. Actuators, A 128(1), 78–83 (2006)

    Article  Google Scholar 

  14. 14.

    L. Le Brizoual et al., GHz frequency zno/si saw device. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 55(2), 442–450 (2008)

    Article  Google Scholar 

  15. 15.

    Kim H et al., Development of ZnO thin films for SAW devices by the ultrasonic spray pyrolysis technique, in Ultrasonics Symposium, 1998. Proceedings, 1998 IEEE, vol. 1 (IEEE, 1998)

  16. 16.

    Visser JH, et al., Surface acoustic wave filters in ZnO-SiO/sub 2/-Si layered structures, in Ultrasonics Symposium, 1989. Proceedings, 1989 (IEEE 1989)

  17. 17.

    C.K. Campbell, C.B. Saw, Analysis and design of low-loss SAW filters using single-phase unidirectional transducers. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 34(3), 357–367 (1987)

    Article  Google Scholar 

  18. 18.

    M. Zhang et al., Effect of sputtering power on nano-mechanical properties of ZnO film. Int. J. Mater. Struct. Integr. 9(4), 236–243 (2015)

    Article  Google Scholar 

  19. 19.

    M. Kadota, M. Makoto, Piezoelectric properties of ZnO films on a sapphire substrate deposited by an RF-magnetron-mode ECR sputtering system. Jpn. J. Appl. Phys. 37(part 1), 2923–2926 (1998)

    Article  Google Scholar 

  20. 20.

    Y.Q. Fu et al., Recent developments on ZnO films for acoustic wave based bio-sensing and microfluidic applications: a review. Sens. Actuators, B 143(2), 606–619 (2010)

    Article  Google Scholar 

  21. 21.

    O. Kawachi et al., Optimal cut for leaky SAW on LiTaO/sub 3/for high performance resonators and filters. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 48(5), 1442–1448 (2001)

    Article  Google Scholar 

Download references

Acknowledgements

Support from the National Science Foundation (NSF) under Grant No. ECCS-1349245 is gratefully acknowledged by the authors. Burak Yildirim also acknowledges the scholarship support from the Ministry of National Education of Turkey.

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Yildirim, B., Tigli, O. Comprehensive characterization of ZnO thin films for surface acoustic wave applications. J Mater Sci: Mater Electron 30, 14621–14630 (2019). https://doi.org/10.1007/s10854-019-01834-8

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