Enhanced performance of 17.7 GHz SAW devices based on AlN/diamond/Si layered structure with embedded nanotransducer

Abstract

Surface acoustic wave (SAW) devices using embedded interdigital transducers (IDTs) on an AlN/diamond/Si layered substrate are fabricated, and their performances are investigated. The Sezawa mode is the dominant resonance with the highest resonant frequency up to 17.7 GHz, a signal amplitude of 20 dB, and an electromechanical coupling coefficient of 0.92%. Comparing these SAW devices with those having the conventional IDTs on the same layered structure, the output SAW power and resonant frequency of devices are improved by 10.7% and 1.1%, respectively, for the embedded IDT devices. This is because the different field distribution leads to the different Bragg reflection and phase velocity for the two types of IDTs. The radiation frequency characteristics indicate that the advantages of the embedded IDTs would be useful for high frequency, high power applications such as monolithic integrated millimeter-wave integrated circuit and high speed communications.

Enhanced Performance of ZnO/SiO2/Al2O3 Surface Acoustic Wave Devices with Embedded Electrodes

“…Meanwhile, it is noted that the displacement of the embedded IDT structure is more drastic than that of the conventional IDT structure. This is likely due to the fact that the energy distribution in electrodes is relatively small in the embedded IDT structure compared to the conventional IDT structure, which can decrease the Bragg reflection and acoustic scattering in the surface of the IDT region, thus yielding a more drastic displacement. , As previous studies pointed out, different configurations of IDT electrodes will result in different distributions of the SAW field and electric field. If the SAW field distribution matches well with the electric field generated by IDTs, the SAW will be more efficiently excited and K 2 can be enhanced. , In this work, when the IDTs are embedded under the piezoelectric layer, energy degradation in non-piezoelectric IDT electrodes is decreased and SAW is efficiently excited in piezoelectric films, so that the enhancement of K 2 can be realized.…”

“…Surface acoustic wave (SAW) devices have been used in industrial applications such as front-end filters, sensors, and oscillators for decades. − Nowadays, with the coming of the 5G era, the requirements for the performance of SAW devices are continuously increasing, such as a wider bandwidth, , smaller size, and lower temperature coefficient of frequency (TCF). − Compared with traditional SAW devices built on discrete piezoelectric substrates, such as LiTaO 3 and LiNbO 3 , layered structures utilizing piezoelectric films (e.g., AlN, ZnO, and PZT) grown on non-piezoelectric substrates (e.g., Si and sapphire (Al 2 O 3 )) have captured intensive attention due to their suitable piezoelectricity, low power consumption, and good integration with integrated circuits. − Among these combinations of piezoelectric films and substrates, ZnO/Al 2 O 3 devices were widely explored recently because ZnO films possess good piezoelectricity and can be easily deposited while Al 2 O 3 is a promising substrate due to its high stability and low cost. − Besides, a small lattice mismatch between ZnO/Al 2 O 3 is beneficial to reduce the insertion loss in SAW devices. , …”

Graphene-Based Fully Transparent Thin Film Surface Acoustic Wave Devices for Sensing and Lab-on-Chip Applications

“…Previously, we developed the transparent ZnO SAW devices using aluminum doped ZnO (AZO) as the electrodes on transparent ZnO/glass layer structures with reasonably good performance [17]. However, to achieve low resistance AZO IDTs, the thickness of AZO film should be at least 500 nm, which deteriorates the transmission properties of the SAW devices and performance of the SAW devices due to mass loading effect [9]. In order to further improve the performance, alternative materials are necessary for the transparent SAW devices.…”

High-shear-velocity Composite Acoustic Materials of AlN/Diamond for Biological MEMS Devices

“…There are many researchers studying the Rayleigh SAW of (002) AlN films on (111) diamond for application in high-velocity SAW substrates. (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) Different orientations of piezoelectric films will form different acoustic properties. Recently, the Rayleigh SAW mode of (100) AlN films on (111) diamond with propagation along the z-axis has been studied and excellent SAW properties were exhibited.…”