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Enhanced Microwave Commutation Quality Factor of Tunable Capacitors Based on SrTiO3 Thin Films
Andrei Tumarkin1, Alexey Bogdan1, Eugeny Sapego1
1Department of Physical Electronics and Technology, Saint Petersburg Electrotechnical University "LETI", 197022 Saint Petersburg, Russia.
Molecules (Basel, Switzerland)
|December 11, 2025
Summary
Strontium titanate thin films on alumina show excellent microwave properties. These novel capacitors offer superior tunability and low loss for advanced electronic applications.
Area of Science:
- Materials Science
- Electrical Engineering
- Condensed Matter Physics
Background:
- Strontium titanate (SrTiO3) is a promising material for microwave applications due to its dielectric properties.
- Developing high-performance ferroelectric elements for tunable microwave devices is an ongoing challenge.
Purpose of the Study:
- To grow high-quality strontium titanate thin films on polycrystalline aluminum oxide substrates.
- To fabricate and characterize planar SrTiO3 capacitors for microwave applications.
- To evaluate the performance of these capacitors in terms of tunability, Q-factor, and capacitance relaxation.
Main Methods:
- Thin films of strontium titanate were deposited using magnetron sputtering.
- Planar capacitors were fabricated using the SrTiO3 films on alumina substrates.
- Microwave properties, including tunability, Q-factor, and capacitance relaxation, were measured.
Main Results:
- The SrTiO3 films exhibited high structural quality and nonlinear properties.
- Planar capacitors demonstrated a tunability of 1.65 and a microwave Q-factor of at least 110.
- Low capacitance relaxation (≤4%) and a high commutation quality factor (CQF) of 3300 were achieved.
- These results surpass previously published data for planar ferroelectric elements.
Conclusions:
- The successful fabrication of SrTiO3 planar capacitors on alumina represents a significant advancement.
- These devices offer superior performance characteristics for tunable microwave applications.
- The demonstrated properties indicate strong potential for integration into next-generation electronic systems.
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