| 摘要 |
Provided are a paraelectric thin film structure and a high frequency tunable device with the paraelectric thin film structure. The paraelectric thin film structure has a large dielectric constant tuning rate and a low dielectric loss at a high frequency. The paraelectric thin film structure includes a perovskite ABO<SUB>3 </SUB>type paraelectric film formed on an oxide single crystal substrate. The paraelectric film is formed of a material selected from Ba(Zr<SUB>x</SUB>,Ti<SUB>1-x</SUB>)O<SUB>3</SUB>, Ba(Hf<SUB>y</SUB>,Ti<SUB>1-y</SUB>)O<SUB>3</SUB>, or Ba(Sn<SUB>z</SUB>,Ti<SUB>1-z</SUB>)O<SUB>3</SUB>. Instead of the paraelectric film, the paraelectric thin film structure may include a compositionally graded paraelectric film having at least two paraelectric films formed of the selected material by varying the composition ratio x, y, or z. A high-frequency/phase tunable device employing the paraelectric thin film structure can have improved microwave characteristics and high-speed, low-power-consuming, low-cost characteristics.
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