| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 98 === In this study, we produced BST bulk and thick film doped with Bi2O3 and B2O3. The contents of doping were 0.5wt%, 1wt% and 2wt%. Thick film was deposited on Pt/Al2O3 substrates by screen printing, and MIM structures were fabricated. We analized the crystallization and electric properties of the BST bulk and thick film.
The crystallization and microstructure were obtained by XRD, SEM and EDS measurement. The electrical properties of C-V were obtained by using Agilent E4980A Precision LCR Meter, and calculated the relative dielectric constants.
From the properties measurements of bulk shrinkage, density and measurements, we found the doping concentration of 1wt% presented the greater density and relative dielectric constant than these without doped. As the doped bulk of glass was sintered at 1250 ℃, the second phase was generated which lead to the increase of dielectric loss.
In the experiment of thick film, we found the dielectric tunability increasing with the sintering temperature because large grain size had the small internal stress. In conclusion samples with large grains have greater tunability.
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