Large dielectric constant (ε/ε0〉6000) Ba0.4Sr0.6TiO3 thin films for high-performance microwave phase shifters
| ISSN: |
1077-3118
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| Source: |
AIP Digital Archive
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| Topics: |
Physics
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| Notes: |
We deposited epitaxial Ba0.4Sr0.6TiO3 (BST) films via laser ablation on MgO and LaAlO3 (LAO) substrates for tunable microwave devices. Postdeposition anneals (∼1100 °C in O2) improved the morphology and overall dielectric properties of films on both substrates, but shifted the temperature of maximum dielectric constant (Tmax) up for BST/LAO and down for BST/MgO. These substrate-dependent Tmax shifts had opposite effects on the room-temperature dielectric properties. Overall, BST films on MgO had the larger maximum dielectric constant (ε/ε0≥6000) and tunability (Δε/ε≥65%), but these maxima occurred at 227 K. 30 GHz phase shifters made from similar films had figures of merit (ratio of maximum phase shift to insertion loss) of ∼45°/dB and phase shifts of ∼400° under 500 V (∼13 V/μm) bias, illustrating their utility for many frequency-agile microwave devices. © 2000 American Institute of Physics.
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| Type of Medium: |
Electronic Resource
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| URL: |