Abstract
Researchers at the University of
Central Florida have developed a novel, low-cost acoustoelectric (AE)
amplification scheme that resolves the issues found in transistor-based
amplifiers and existing AE amplification systems. All transistor-based
amplifiers suffer from a decrease in optical power (gain) as the frequency
increases, and though current AE amplification systems can provide greater
gain-frequency, they have low operating efficiency and low electromechanical
coupling.
In contrast, the UCF AE amplification mechanism operates
more efficiently and offers higher gains as the frequency increases. Using lateralextensional thin-film piezoelectric-on-silicon (TPoS) resonant cavities, the
invention amplifies bulk acoustic waves in a structure with high
electromechanical coupling. As a result, the innovation enables transistor-less
amplification at both lower and higher frequencies and non-reciprocal devices.
Manufacturers can use the new scheme to build more cost-effective, low-power,
low-loss devices for communications, wireless sensors, and the Internet of
Things (IoT). Example acoustic devices include unilateral amplifiers, zero-loss
filters, oscillators, and circuit-less, high-detection range wireless sensors.
Technical Details
The new UCF apparatus comprises a semiconductor layer and a
thin piezoelectric layer (such as TpoS) deposited/bonded
onto the semiconductor layer to form an acoustic cavity. Within the composite
structure, the energy exchange between the propagating acoustic waves of the
piezoelectric medium and the charge carriers in the semiconductor would
normally lead to acoustoelectric loss.
However, by pumping energy into the semiconductor layer to form an electric
field across it, the velocity of the charge carriers exceeds that of the
acoustic waves. As a result, the energy transfer reverses (from the charge carriers
to the acoustic waves), effectively amplifying the acoustic waves, so that as
the frequency of operation increases, the achievable gain also increases.
In one example setup, the thin piezoelectric layer consists
of 1 _m (20 percent) of scandium doped aluminum nitride (Sc0.2Al0.8N),
and the semiconductor layer comprises 2 _m of lightly doped n-type Si. Access
pads inject DC current into the semiconductor layer to form an electric field in
parallel with the direction of acoustic wave propagation in the semiconductor
layer.
Partnering Opportunity
The research team is looking for partners to develop the
technology further for commercialization.
Stage of Development
Prototype available.
Benefit
Lower power consumption compared to conventional transistor-based amplifiersSmall footprint, near-zero insertion lossFabrication of new devices without using active circuit componentsElimination of power-hungry semiconductor amplifiers in all RF device applicationsMarket Application
Low-power, low-loss devices for communications, wireless sensors, and the Internet of Things (IoT)
Brochure
