Abstract

ZnO thin films were deposited on Al and Pt electrodes by an RF reactive sputtering system for the fabrication of FBAR (film bulk acoustic wave resonator), and the effect of thermal treatment temperature on their c-axis preferred orientation was investigated. SEM experiments show that columnar structure of ZnO thin films were grown with c-axis normal to electrode material, and XRD experiments show that both ZnO films were grown with (002) plane preferred orientation, but larger diffraction peak was observed with Pt electrode. The peak intensity increased with higher thermal treatment temperature, but c-axis preferred orientation was diminished. The surface roughness of Al thin film was higher than that of Pt, and these affect the surface roughness of ZnO film deposited on the electrode. Though the preferred orientation with respect to Pt(111) plane was improved with higher thermal treatment temperature, this could not improve the c-axis orientation of ZnO film.

Keywords

• FBAR;
• ZnO;
• Preferred orientation;
• Surface roughness

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References

1. IEEE Trans. Microwave Theory & Tech. v.49 Thin-film bulk acoustic resonators and filters using ZnO and lead-zirconium-titanate thin films Q.Su;P.Kirby;E.Komuro;M.Imura;Q.Zhang;R.Whatmore https://doi.org/10.1109/22.915462
2. IEEE MTT-S Digest Application of film bulk acoustic resonators S.Horwitz;C.Milton
3. Proc. IEEE Frequency Control Symp. Micromachined thin film bulk acoustic resonators R.Ruby;P.Merchant
4. IEEE MTT-S Digest High Q microwave acoustic resonators and filters M.Lakin;G.Kline;K.McCarron
5. Proc. IEEE Ultrasonic Symp. ZnO based thin film bulk acoustic wave filters for EGSM band J.Kaitila;M.Ylilammi;J.Molarius
6. Proc. IEEE Ultrasonic Symp. Film bulk acoustic wave resonator technology S.Krishnaswamy;J.Rosenbaum;S.Horwitz;C.Vale;R.Moore
7. J. European Ceramic Soc. v.21 Materials for bulk acoustic wave resonators and filters H.Lobl;M.Klee;R.Milsom;R.Dekker;C.Metzmacher;W.Brand;P.Lok https://doi.org/10.1016/S0955-2219(01)00329-6
8. J. of KIEEME v.11 Characteristics of ZnO/glass thin films prepared by RF magnetron sputtering Y.Park;S.Yoon;J Choi;H.Kim;H.Jung;C.Park
9. J. of KIEEME v.13 A study on c-axis preferred orientation on ZnO thin film at Ar/O2 gas ratios D.Lee;Y.Park;S.Nahm;J.Lee;H.Kim;S.Yoon;K.Whang
10. Proc. IEEE Ultrasonic Symp. Effect of the sputtering parameters on the growth and piezoelectric properties of zinc oxide thin films V.Kutepova;D.Hall
11. Jpn. J. Appl. Phys. v.39 Film bulk acoustic resonator fabrication for radio frequency filter applications S.Park;B.Seo;H.Park;G.Yoon https://doi.org/10.1143/JJAP.39.4115