| Summary: | 碩士 === 長庚大學 === 化工與材料工程研究所 === 94 === The objectives of this research are to prepare piezoelectric PZT thick films by micro-powder-sol-gel method and to apply these PZT thick films fabricate in surface acoustic wave (SAW) filters. In addition, through the investigation of the effects of the precursor preparation conditions of the micro-powder-sol-gel method on the characteristics of precursor solutions, micro-powders, thick films and the SAW filters, it is hoped that ultimately the correlation between these process variables and the characteristics of materials and devices as well as the mechanism involved can be found to enhance the performance of the SAW filters.
From the experimental results, it was shown that the preparation conditions of the precursor solutions including concentration, amount of hydrolysis water, selection of reactants have effects not only on the properties of the micro-powders and the thick films but also on the performance of the SAW filters. These differences were probably attributed to the difference in the ratio of hydrolysis to condensation rate. From the study of the effects of process conditions on the properties of the materials, it was found that PZT thick films prepared from the precursor slurry solutions of 0.1 M PZT 8 system possessed best electrical properties (Pr=40.5 μC/cm2、εr =2475.20、d31=-757.99 pC/N and d33=1659.97 pC/N at 1 kHz) after being soft-baked at 350℃ for 10 minutes and hard-baked at 600℃ for 60 minutes. For SAW filters prepared from precursor slurry solutions of different concentrations and different amounts of hydrolysis water, the SAW Filters prepared 0.1 M precursor slurry solutions without the addition of hydrolysis water were found to have the best filtering performance with the center frequency 586 Hz and insertion loss of device 14.326 dB, respectively.
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