c-Axis-tilted ScAlN films grown on silicon substrates for surface acoustic wave devices

2022 ◽  
Author(s):  
Takumi Tominaga ◽  
Shinji Takayanagi ◽  
Takahiko Yanagitani
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Mobile Networks ◽  
Tilt Angle ◽  
Silicon Substrate ◽  
Electromechanical Coupling ◽  
Rf Magnetron Sputtering ◽  
Electromechanical Coupling Coefficient ◽  
Silicon Substrates ◽  
Device Structure

Abstract ScAlN films are currently being investigated for their potential use in surface acoustic wave (SAW) devices for next-generation mobile networks because of their high piezoelectricity. This paper describes the numerical simulation of SAW propagation in c-axis-tilted ScAlN films on silicon substrates and a fabrication technique for preparing c-axis-tilted ScAlN films on silicon substrates. The electromechanical coupling coefficient K 2 of SAW propagating in the ScAlN film/silicon substrate increased due to the c-axis tilt angle. The maximum K 2 value is approximately 3.90%. This value is 2.6 times the maximum K 2 value of the c-axis-oriented ScAlN film/silicon substrate structure. The c-axis-tilted ScAlN films with an Sc concentration of 40% were prepared on a silicon substrate via RF magnetron sputtering based on the self-shadowing effect, and the maximum c-axis tilt angle was 57.4°. These results indicate that this device structure has potential for SAW device applications with well-established micromachining technology derived from silicon substrates.

Surface acoustic wave resonator from thick MOVPE-grown layers of GaN(0001) on sapphire

2002 ◽  
Vol 743 ◽  
Author(s):  
Sverre V. Pettersen ◽  
Thomas Tybell ◽  
Arne Rønnekleiv ◽  
Stig Rooth ◽  
Veit Schwegler ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Electromechanical Coupling ◽  
Film Surface ◽  
Center Frequency ◽  
Electromechanical Coupling Coefficient ◽  
Nitride Film ◽  
Wave Resonator ◽  
Lift Off ◽  
Definition Of

ABSTRACTWe report on fabrication and measurement of a surface acoustic wave resonator prepared on ∼10m thick GaN(0001) films. The films were grown by metal-organic vapor phase epitaxy on a c-plane sapphire substrate. The surface morphology of the films were examined with scanning electron and atomic force microscopy. A metallic bilayer of Al/Ti was subsequently evaporated on the nitride film surface. Definition of the resonator interdigital transducers, designed for a wavelength of λ=7.76m, was accomplished with standard UV lithography and lift-off. S-parameter measurements showed a resonator center frequency f0=495MHz at room temperature, corresponding to a surface acoustic wave velocity of 3844m/s. The insertion loss at center frequency was measured at 8.2dB, and the loaded Q-factor was estimated at 2200. Finally, measurements of the resonator center frequency for temperatures in the range 25–155°C showed a temperature coefficient of -18ppm/°C. The intrinsic GaN SAW velocity and electromechanical coupling coefficient were estimated at νSAW=383 1m/s and K2=1.8±0.4·10−3.

Surface Acoustic Wave Device on (AlN/LGS) Substrate

2007 ◽  
Vol 124-126 ◽  
pp. 53-56
Author(s):  
Sean Wu ◽  
Zhi Xun Lin ◽  
Maw Shung Lee
Keyword(s):  
Thin Films ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Electromechanical Coupling ◽  
Chemical Properties ◽  
Temperature Stability ◽  
Rf Magnetron Sputtering ◽  
High Temperature Stability ◽  
Saw Devices ◽  
Stable Chemical

Langasite (La3Ga5SiO14 or abbreviated as LGS) single crystal is an attractive substrate for surface acoustic wave (SAW) devices requiring good temperature stability and higher electromechanical coupling constant than quartz. AlN thin films are attractive materials that have some excellent characteristics, such as high SAW velocity, piezoelectricity, high-temperature stability, and stable chemical properties. In this study, AlN thin films were deposited on LGS to be a new composite SAW substrate (AlN/LGS) by reactive RF magnetron sputtering method. SAW delay-line device was manufactured on this substrate. The performance of the device was measured by network analyzer (Agilent 8753E).The results exhibited the composite substrate (AlN/LGS) increased the Rayleigh wave velocity, decreased the insertion loss of SAW devices, and suppressed the harmonic response.

scholarly journals Surface acoustic wave temperature properties in alpha-GeO2 crystal

2021 ◽  
Vol 2131 (5) ◽  
pp. 052098
Author(s):  
R M Taziev
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Acoustic Wave ◽  
Temperature Coefficient ◽  
Surface Acoustic Wave ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Propagation Direction ◽  
Electromechanical Coupling Coefficient ◽  
Wave Propagation Direction

Abstract In this study, the surface acoustic wave (SAW) temperature properties in flux-grown α-GeO2 crystal are numerically investigated. It is shown that the SAW velocity temperature change substantially depends only on the temperature coefficient of three elastic constants: C66, C44 and C14 for crystal cuts and wave propagation directions, where SAW has high electromechanical coupling coefficient. The SAW temperature coefficient of delay (TCD) for these crystal cuts are in the range from -40 ppm /°C to -70 ppm /°C. In contrast to alpha-quartz, the surface wave TCD values are not equal to zero in Z-, Y- , and Z- rotated cuts of α-GeO2 single crystal. Its values are comparable in the magnitude with the surface wave TCD values in lithium tantalate. In the crystal grown from the melt, the interdigital transducer (IDT) conductance has two times larger amplitude than that in hydrothermally grown a-GeO2. The leaky acoustic wave excited by IDT on Z+120°-cut and wave propagation direction along the X-axis, has an electromechanical coupling coefficient 5 times less than that for surface wave.

scholarly journals SILICON COMPATIBLE ACOUSTIC WAVE RESONATORS: DESIGN, FABRICATION AND PERFORMANCE

2014 ◽  
Vol 15 (2) ◽  
Author(s):  
Aliza Aini Md Ralib ◽  
Anis Nurashikin Nordin
Keyword(s):  
Acoustic Wave ◽  
Quality Factor ◽  
Surface Acoustic Wave ◽  
Insertion Loss ◽  
Electromechanical Coupling ◽  
High Reliability ◽  
Bulk Acoustic Wave ◽  
Electromechanical Coupling Coefficient ◽  
Single Chip ◽  
Acoustic Wave Resonators

ABSTRACT: Continuous advancement in wireless technology and silicon microfabrication has fueled exciting growth in wireless products. The bulky size of discrete vibrating mechanical devices such as quartz crystals and surface acoustic wave resonators impedes the ultimate miniaturization of single-chip transceivers. Fabrication of acoustic wave resonators on silicon allows complete integration of a resonator with its accompanying circuitry.  Integration leads to enhanced performance, better functionality with reduced cost at large volume production. This paper compiles the state-of-the-art technology of silicon compatible acoustic resonators, which can be integrated with interface circuitry. Typical acoustic wave resonators are surface acoustic wave (SAW) and bulk acoustic wave (BAW) resonators.  Performance of the resonator is measured in terms of quality factor, resonance frequency and insertion loss. Selection of appropriate piezoelectric material is significant to ensure sufficient electromechanical coupling coefficient is produced to reduce the insertion loss. The insulating passive SiO2 layer acts as a low loss material and aims to increase the quality factor and temperature stability of the design. The integration technique also is influenced by the fabrication process and packaging.  Packageless structure using AlN as the additional isolation layer is proposed to protect the SAW device from the environment for high reliability. Advancement in miniaturization technology of silicon compatible acoustic wave resonators to realize a single chip transceiver system is still needed. ABSTRAK: Kemajuan yang berterusan dalam teknologi tanpa wayar dan silikon telah menguatkan pertumbuhan yang menarik dalam produk tanpa wayar. Saiz yang besar bagi peralatan mekanikal bergetar seperti kristal kuarza menghalang pengecilan untuk merealisasikan peranti cip. Silikon serasi  gelombang akustik resonator mempunyai potensi yang besar untuk menggantikan unsur-unsur diskret kerana keupayaan untuk mengintegrasikan dengan litar yang disertakan itu. Integrasi ini membawa kepada peningkatan prestasi, fungsi yang lebih baik dengan pengurangan kos pada pengeluaran jumlah yang besar. Oleh itu, Karya ini mengkaji silikon resonator akustik yang serasi, yang bersepadu dengan muka litar untuk membolehkan integrasi yang lengkap. Resonator gelombang akustik yang digunakan adalah gelombang permukaan akustik ( SAW ) dan gelombang akustik pukal ( BAW ) resonator . Kriteria penting untuk menilai prestasi resonator seperti faktor kualiti, frekuensi resonans dan kehilangan sisipan juga digariskan dalam setiap kerja sebelumnya. Pemilihan bahan piezoelektrik yang sesuai adalah penting untuk memastikan pekali gandingan elektromekanik yang mencukupi dihasilkan untuk mengurangkan kehilangan sisipan. Lapisan tambahan pasif SiO2   yang bertindak sebagai bahan rendah sisipan dipercayai meningkatkan faktor kualiti dan kestabilan suhu reka bentuk. Teknik integrasi juga dipengaruhi oleh proses fabrikasi dan pembungkusan. Struktur tanpa pembungkusan menggunakan AlN sebagai lapisan pengasingan tambahan itu dicadangkan untuk melindungi peranti SAW dari persekitaran untuk kebolehpercayaan yang tinggi. Banyak lagi kemajuan perlu dilakukan dalam pengecilan silikon serasi resonator gelombang akustik untuk merealisasikan sistem cip transceiver tunggal.KEYWORDS: RF-MEMS; piezoelectric; resonator; surface acoustic wave (SAW);bulk acoustic wave (BAW); FBAR

SURFACE-ACOUSTIC-WAVE FIELD AND ACOUSTO-OPTIC INTERACTION IN AlN/128-DEG-ROTATED Y-CUT X-PROPAGATION LiNbO3

2013 ◽  
Vol 27 (05) ◽  
pp. 1350032
Author(s):  
JUNTAO WANG ◽  
QUN HAN ◽  
JIPING NING ◽  
YANG HE
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Diffraction Efficiency ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Guided Wave ◽  
Electromechanical Coupling Coefficient ◽  
Overlap Integral ◽  
Aln Film ◽  
First Time

The efficiency of guided-wave acousto-optic (AO) interaction in AlN /128-deg-rotated Y-cut X-propagation lithium niobate (128-deg YX- LiNbO 3) structure is analyzed theoretically for the first time by determining the overlap integral between the optical and the surface acoustic wave (SAW) field distribution. The results show that the use of an AlN film can increase the phase velocity of SAW, the electromechanical coupling coefficient and the diffraction efficiency of AO interaction. A maximum of 9.33% for the electromechanical coupling coefficient is obtained when the normalized thickness of AlN film equals 0.09. The diffraction efficiency has a significant improvement when the normalized thickness of AlN film is increased from 0 to 0.05. And, the improvement for the TM polarization is more evident than that for the TE polarization. However, for a well-concentrated optical waveguide, the use of an AlN film reduces the diffraction efficiency of the TM polarization when the SAW frequency is low.

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