
3D resonator for mmwave spectral processor
Researchers in the US have developed a 3D ferroelectric resonator in CMOS to reduce the size of millimetre wave wireless devices.
The researchers at the University of Florida developed a 3D fin-based nano-acoustic ferroelectric resonator in a CMOS process for spectral processors that can operate across many different bands, including mmwave.
The team, led by Dr Roozbeh Tabrizian, associate professor in UF’s Department of Electrical and Computer Engineering, began work on this new approach to building acoustic resonators. These are made from 3D silicon nano-fins with hafnia–zirconia ferroelectric gates wrapped around them in a CMOS process.
With the advent of AI and autonomous devices, the increased demand will require more frequencies, including mmwave at 26GHz for the latest 5G and 6G bands This requires massive arrays of radiofrequency filters for adaptive signal shaping at arbitrary frequencies. However, it is difficult to create massively integrated arrays using conventional filters based on planar acoustic resonators due to their large footprint and limited on-chip frequency scalability or intrinsic configurability.
The 3D resonators can be used to make highly integrated voltage-controlled spectral processors with intrinsic switching that operate in the mmwave bands.
The ferroelectric-gate fins are created by growing atomic-layered ferroelectric hafnia-zirconia transducers on silicon nano-fins. The resonator generates bulk acoustic modes with scalable frequencies over 3–28 GHz, defined lithographically by the fin width.
The voltage-controlled tuneability of the gate-transducer polarization also enables intrinsic configurability without the need for external switches. The resonators were used to create a monolithic filter array, created by electrical coupling of ferroelectric-gate fins implemented on a single die, covering 9–12 GHz, providing dynamic configurability of the active passband and an isolation as large as 17 dB.
“This entirely new type of spectral processor, which integrates different frequencies on one monolithic chip, is truly a game changer,” said David Arnold, associate chair for faculty affairs in the Department of Electrical and Computer Engineering at Florida. “Dr. Tabrizian’s new approach for multi-band, frequency-agile radio chipsets not only solves a huge manufacturing challenge, but it also allows designers to imagine entirely new communication strategies in an increasingly congested wireless world. Put more simply, our wireless devices will work better, faster, and more securely.”
