Interdigital transducer

Fabrication

Bandwidth (computing)

Materials science

Layer (electronics)

Surface acoustic wave

Telecommunications

Ultrasonic sensor

Computer science

Acoustics

Acoustic wave

Acoustic impedance

Alternative medicine

Transducer

Physics

Wideband

Optics

Lithium niobate

Resonator

Composite material

Medicine

Piezoelectricity

Optoelectronics

Pathology

Japanese Journal of Applied Physics

"Hetero acoustic layer (HAL) surface acoustic wave (SAW) device" is a new type of SAW device using a single crystal piezoelectric thin plate supported by a substrate. In this study, a HAL SAW resonator using a LiNbO3 (LN) thin plate and a multi-layer acoustic film was designed by finite element method (FEM) and fabricated. The thickness of LN is 3.6 µm and the pitch of an interdigital transducer (IDT) (λ) is 5.24 µm for a resonance frequency of 600 MHz. The multi-layer acoustic film is composed of 3 layers of SiO2 and AlN for each, i.e., 6 layers in total, alternately deposited on a glass substrate. The HAL SAW resonator achieved a wide bandwidth of 20.3% and a high impedance ratio of 83 dB. Compared with a 0th shear horizontal (SH0) mode plate wave resonator, the performance is better and the thickness of LN is 7 times larger. The HAL SAW without a cavity is advantageous in terms of mechanical stability, thickness controllability and fabrication yield.

Wideband acoustic wave resonators composed of hetero acoustic layer structure