Temperature-compensated surface-acoustic-wave devices with SiO2 film overlays

Parker, T.E.; Wichansky, H.

doi:10.1063/1.326116

Cited by 82 publications

(31 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, they show significantly higher TCF 1 of about 100 ppm/K. It has been found earlier that different cuts of LiTaO 3 and LiNbO 3 in combination with SiO 2 layers can provide temperature-compensated systems [73,74]. Hence, 36 8 YX-LiTaO 3 /SiO 2 systems can yield first-and second-order temperature compensation and thus no temperature control is needed for a large temperature range.…”

Section: Love Wave Sensorsmentioning

confidence: 99%

Microacoustic Sensors for Liquid Monitoring

et al. 2001

View full text Add to dashboard Cite

In recent years, much effort has been expended to developing miniaturized, reliable sensors for measuring physical and chemical liquid properties. Microacoustic devices may be employed to determinate physical quantities perturbing the propagation conditions of the acoustic wave, even in liquid environments. For liquid sensors, acoustic modes with shear polarization are often used in order to avoid radiation losses. Examples are shear bulk modes, surface skimming bulk waves, shear-horizontal acoustic plate modes, and Love modes. Furthermore, modes with sagittal polarization may be applied if their phase velocity is sufficiently lower than the sound velocity in the adjacent liquid. General interactions between acoustic waves and liquids are viscous coupling, acoustoelectric effects, and mass loading. The resulting changes in device frequency and attenuation may be utilized for sensing purposes.The general advantages of microacoustic sensors are high sensitivity, simple fabrication, and quasidigital frequency readout. Hence, a wide variety of devices based on different modes for very different applications has been discussed in the relevant literature. The aim of this review is to provide a systematic overview of microacoustic sensors particularlay suited for operation in liquids.First, we provide a brief introductionto surfaceacousticwave devices and the underlying physics, basic microacoustic structures, and general measurement techniques. A description of the mechanisms of interaction between liquids and acoustic waves is then followed by a comprehensive survey covering the different types of microacoustic liquid sensors, with emphasis on the mode-specific device properties. Thereafter, aspects of material selection and device fabrication are summarized. Lastly, an overview is given indicating where microacoustic liquid sensors have already been put into practice and where their application may be expected in the near future.

show abstract

Section: Love Wave Sensorsmentioning

confidence: 99%

Microacoustic Sensors for Liquid Monitoring

et al. 2001

View full text Add to dashboard Cite

show abstract

“…One of the major results was the discovery of the ST-cut for quartz that yields a zero TCD, for the Rayleigh SAW [10]. For other materials such as LiTaO 3 , efforts have been made to achieve zero TCD, by adding an overlayer (e.g., SiO 2 ), the thickness of which allows tuning of the TCD [9]. This configuration yields a dispersive generalized Rayleigh SAW.…”

Section: Discussionmentioning

confidence: 99%

“…The material parameters and their temperature dependence 3 have been taken from [7]- [9]. The analysis has been performed for 25…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Substrates for zero temperature coefficient Love wave sensors

Jakoby

Vellekoop²

2000

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

Abstract-Microacoustic Love wave delay lines show high sensitivity to perturbations such as mass depositions on the wave-guide surface. Furthermore, because of their shear polarization, Love waves are ideally suited for liquid sensing applications. Using a Love wave delay line as feedback element in an oscillator allows the realization of viscosity sensors, and, using a chemical interface, chemical sensors, where the output signal is the oscillation frequency. To achieve a high effective sensitivity, the cross-sensitivity to temperature has to be kept low. We outline the proper choice of a material and especially focus on the influence of crystal cut and the major device design parameters (mass sensitivity and coupling coefficient) on the temperature coefficient of the sensor.

show abstract

“…It is also possible to trim the frequency of patterned SAW wafer by depositing dielectric thin films on the wafer [1] but this method is usually done nowadays for the purpose of finger shorting protection from metallic particles. Dielectric thin film deposition is also being used to achieve better temperature coefficient of delay (TCD) [2,3] . Reactive ion etch can be used to trim assembled SAW devices prior to encapsulation.…”

Section: Introductionmentioning

confidence: 99%

In-situ frequency trimming of SAW resonator using conventional crystal resonator fine tuning method with gold thin film addition

Wang¹,

Wang²,

Lo³

et al.

IEEE Symposium on Ultrasonics, 2003

View full text Add to dashboard Cite

SAW devices are routinely frequency trimmed at the wafer level prior to the dicing process so to improve yield at the assembly level. The trimming can be achieved by using wet etching, reactive ion etching, ion beam milling, and other methods. It is also possible to trim the frequency of patterned SAW wafer by depositing dielectric thin films on the wafer but this method is usually done for the purpose of finger shorting protection from metallic particles. Reactive ion etching can be used to trim assembled SAW devices prior to encapsulation. This is seldom employed since it is considered costly, inefficient, and difficult to perform in-situ. In this paper we propose trimming assembled SAW resonator (SAWR) by using the conventional crystal resonator fine-tuning process with gold thin film addition. Nowadays, the fine-tuning process is a necessary step in crystal resonator production. We show that this is a simple and well-controlled method to trim assembled SAW resonator also. This method provides a wide trimming range and the gold film is thin enough not to short out the SAW transducers so that the SAWR's integrity can be maintained.

show abstract

Temperature-compensated surface-acoustic-wave devices with SiO2 film overlays

Cited by 82 publications

References 11 publications

Microacoustic Sensors for Liquid Monitoring

Microacoustic Sensors for Liquid Monitoring

Substrates for zero temperature coefficient Love wave sensors

In-situ frequency trimming of SAW resonator using conventional crystal resonator fine tuning method with gold thin film addition

Contact Info

Product

Resources

About