Investigation of GeO2 thin film properties for improvement of temperature coefficient of frequency of SAW devices

2014 ◽  
Author(s):  
Matthias Knapp ◽  
Philipp Jager ◽  
Markus Hauser ◽  
Ulrike Rosler ◽  
Werner Ruile ◽  
...  
Keyword(s):  
Thin Film ◽  
Temperature Coefficient ◽  
Film Properties ◽  
Saw Devices ◽  
Temperature Coefficient Of Frequency

Characteristics Analysis of Saw Filter Using Al0.36Ga0.64N Thin Film

2002 ◽  
Vol 720 ◽  
Author(s):  
Sun-Ki Kim ◽  
Min-Jung Park ◽  
Cheol-Yeong Jang ◽  
Hyun-Chul Choi ◽  
Jung-Hee Lee ◽  
...  
Keyword(s):  
Thin Film ◽  
Insertion Loss ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Side Lobe ◽  
Electromechanical Coupling Coefficient ◽  
Device Performance ◽  
Saw Devices ◽  
Characteristics Analysis ◽  
Temperature Coefficient Of Frequency

AbstractAlxGa1-xN sample with x=0.36 was epitaxially grown on sapphire by MOCVD. SAW velocity of 5420 m/s and TCF (temperature coefficient of frequency) of -51.20 ppm/°C were measured from the SAW devices fabricated on the AlxGa1-xN sample, when kh value was 0.078, at temperatures between –30 °C and 60 °C Electromechanical coupling coefficient was ranged from 1.26 % to 2.22 %. The fabricated SAW filter have shown a good device performance with insertion loss of -33.853 dB and side lobe attenuation of 20 dB.

The Improvement of Temperature Coefficient of Frequency in Thin Film Bulk Acoustic Wave Resonator using Secondary Harmonics

2002 ◽  
Vol 741 ◽  
Author(s):  
Yukio Yoshino ◽  
Masaki Takeuchi ◽  
Hajime Yamada ◽  
Yoshihiko Goto ◽  
Tadashi Nomura ◽  
...  
Keyword(s):  
Thin Film ◽  
Acoustic Wave ◽  
Temperature Coefficient ◽  
Finite Element Method Simulation ◽  
Thickness Ratio ◽  
Bulk Acoustic Wave ◽  
Bulk Acoustic Wave Resonator ◽  
Wave Resonator ◽  
Film Bulk ◽  
Temperature Coefficient Of Frequency

ABSTRACTWe have succeeded in making an 870MHz-range thin film bulk acoustic wave (BAW) resonator that has a small temperature coefficient of frequency (TCF) using secondary harmonics. The 870MHz-range BAW resonator has been requested to have nearly zero TCF, because it will be used in an oscillator for remote keyless entry systems. The BAW resonator has composite structure that consists of Al electrodes and ZnO/SiO2. We directed our attention to the fact that ZnO and Al have negative TCF, and SiO2 has a positive one. It is theoretically possible to make zero TCF BAW resonators by optimizing the thickness ratio of ZnO and SiO2. However, using fundamental resonance, TCF is so sensitive to the thickness ratio that it cannot be easily controlled by MEMS techniques. We founds in finite element method simulation and confirmed by experiment that the TCF of secondary harmonics has a local minimum when changing the ZnO/SiO2 thickness ratio. As the result, a nearly zero TCF resonator without strict control of ZnO/SiO2 thickness ratio has been realized by adopting Al/ZnO/SiO2/ZnO/Al/SiO2 structure and combining thermal oxidized Si and sputtered SiO2. The resonator has the TCF of -1.86ppm/degree in the range of −40 to 85 degrees centigrade.

Transversal Type Piezoelectric Resonator Using ZnO Thin Film on Micro-Fabricated Elinver (Fe-Ni-Cr-Ti) Alloy

1998 ◽  
Vol 518 ◽  
Author(s):  
Y. Yoshino
Keyword(s):  
Thin Film ◽  
Temperature Coefficient ◽  
Cross Section ◽  
Wet Etching ◽  
Ti Alloy ◽  
Zno Thin Film ◽  
Electrical Characteristics ◽  
Piezoelectric Resonator ◽  
Axis Orientation ◽  
Temperature Coefficient Of Frequency

AbstractA transversal type 3.58MHz piezoelectric resonator has been fabricated using piezoelectric ZnO thin film on ELINVER (Fe-Ni-Cr-Ti ) alloy. The ZnO/ELINVER structure piezoelectric resonator has been designed to have 2 ppm temperature coefficient of frequency (TCF) per degree from -20 degrees to 80 degrees centigrade. The temperature coefficient of ELINVER alloy can be controlled to cancel the TCF of ZnO thin film by heat annealing. The ZnO thin film on ELINVER alloy shows c-axis orientation. The c-axis orientation of the ZnO thin film is strongly influenced by the surface roughness of the ELINVER alloy. The wet etching process has been adopted to shape the resonator made from ELINVER alloy substrate. The cross section of the resonator is a structure tapered about 10 degrees, created using different sized photo masks on each side of the ELINVER surface. The tapered cross section of the transversal type resonator greatly improves the frequency characteristics of the resonator. The electrical characteristics of the resonator after the improvement include a resonance frequency of 3.58MHz trimmed by a YAG laser, and resonance resistance of about 200 Ω. The temperature coefficient of frequency is about 1.5 ppm per degree at a temperature range of-20 degrees to 80 degrees centigrade.

Measuring Thin Film Properties Using SAW Devices: Diffusivity and Surface Area

1987 ◽  
Author(s):  
S.J. Martin ◽  
G.C. Frye ◽  
A.J. Ricco ◽  
T.E. Zipperian
Keyword(s):  
Thin Film ◽  
Surface Area ◽  
Film Properties ◽  
Saw Devices

scholarly journals Love Wave Ultraviolet Photodetector Fabricated on a TiO2/ST-Cut Quartz Structure

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Walter Water ◽  
Yi-Shun Lin ◽  
Chi-Wei Wen
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Temperature Coefficient ◽  
Coupling Coefficient ◽  
Love Wave ◽  
Electromechanical Coupling ◽  
Quartz Substrate ◽  
Electromechanical Coupling Coefficient ◽  
Ultraviolet Photodetector ◽  
Temperature Coefficient Of Frequency

A TiO2thin film deposited on a 90° rotated 42°45′ ST-cut quartz substrate was applied to fabricate a Love wave ultraviolet photodetector. TiO2thin films were grown by radio frequency magnetron sputtering. The crystalline structure and surface morphology of TiO2thin films were examined using X-ray diffraction, scanning electron microscope, and atomic force microscope. The effect of TiO2thin film thickness on the phase velocity, electromechanical coupling coefficient, temperature coefficient of frequency, and sensitivity of ultraviolet of devices was investigated. TiO2thin film increases the electromechanical coupling coefficient but decreases the temperature coefficient of frequency for Love wave propagation on the 90° rotated 42°45′ ST-cut quartz. For Love wave ultraviolet photodetector application, the maximum insertion loss shift and phase shift are 2.81 dB and 3.55 degree at the 1.35-μm-thick TiO2film.

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