Resonance Characteristic Improvement of ZnO-Based FBAR Devices Fabricated on Thermally Annealed Bragg Reflectors

  • Yim, Mun-Hyuk (Communication and Electronics Lab (CEL), Information and Communications University(ICU)) ;
  • Kim, Dong-Hyun (CEL, IC) ;
  • Linh Mai (CEL, IC) ;
  • Giwan Yoon (ICU)
  • Published : 2003.12.01


In this paper, we present the thermal annealing effects of the W/$SiO_2$ multi-layer reflectors in ZnO-based FBAR devices with cobalt (Co) electrodes in comparison with those with aluminum (Al) electrodes. Various thermal annealing conditions have been implemented on the W/$SiO_2$ multi-layer reflectors formed on p-type (100) silicon substrates. The resonance characteristics could be significantly improved due to the thermal annealing and were observed to depend strongly on the annealing conditions applied to the reflectors. Particularly, the FBAR devices with the W/$SiO_2$ multi- layer reflectors annealed at $400^{\circ}C$/30min have shown superior resonance characteristics in terms of return loss and quality-factor (Q-factor). In addition, the use of Co electrodes has resulted in further improvement of the resonance characteristics as compared with the Al electrodes. As a result, the combined use of both the thermal annealing and Co electrodes seems very useful to more effectively improve the resonance characteristics of the FBAR devices with the W/$SiO_2$ multi-layer reflectors.


FBAR;Bragg reflector;Thermal annealing;Cobalt electrode;Return loss;and Q-factor


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