Significant resonance characteristic improvements by combined use of thermal annealing and Co electrode in ZnO-based FBARs

Yim, Munhyuk; Kim, Dong-Hyun; Chai, Dongkyu; Yoon, Giwan

doi:10.1049/el:20031029

Cited by 13 publications

(11 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reportedly, the quality of the multilayered BR has an impact on the FBAR characteristics. 5,6) In the as-deposited SiO 2 /W multilayer, some physical defects may exist and/or some poor adhesions may occur at interfaces between the physically deposited films, hence degrading the device performance. Moreover, SiO 2 with a usually amorphous structure is known to have poor adhesion with other materials.…”

Section: 2µmmentioning

confidence: 99%

ZnO-Based Film Bulk Acoustic Resonator Devices Feasible for Worldwide Interoperability for Microwave Access Applications

Pham¹,

Mai²,

Yoon³

2008

jjap

Self Cite

View full text Add to dashboard Cite

In this paper, we describe a novel fabrication technique of ZnO-based film bulk acoustic resonator (FBAR) devices using a new type of multilayered Bragg reflector with very thin chromium (Cr) layers additionally formed between SiO 2 and W layers. Each Cr layer is considered to enhance the adhesion between the SiO 2 and W layers. The fabricated FBAR devices are shown to operate at the frequency range of 2.7 -3.0 GHz, along with good return loss as well as high Q-factors. Furthermore, the effects of bottom electrode thickness on the FBAR device performance are also investigated and compared. This feasibility study indicates that the novel fabrication technique can be useful for future broadband mobile worldwide interoperability for microwave access (WiMAX) applications.

show abstract

Section: 2µmmentioning

confidence: 99%

ZnO-Based Film Bulk Acoustic Resonator Devices Feasible for Worldwide Interoperability for Microwave Access Applications

Pham¹,

Mai²,

Yoon³

2008

jjap

Self Cite

View full text Add to dashboard Cite

show abstract

“…[10][11][12][13] Also, the temperature variations and compensations in the FBAR devices have been investigated. [10][11][12][13] Also, the temperature variations and compensations in the FBAR devices have been investigated.…”

Section: Introductionmentioning

confidence: 99%

Second-order resonant ZnO-based film bulk acoustic resonator devices and thermal techniques to improve their resonant characteristics

Mai

Pham²,

Yoon³

2008

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

Self Cite

View full text Add to dashboard Cite

Articles you may be interested inViscosity sensor using ZnO and AlN thin film bulk acoustic resonators with tilted polar c-axis orientations J. Appl. Phys. 110, 094511 (2011); 10.1063/1.3657781Mass sensitivity of thin film bulk acoustic resonator sensors based on polar c-axis tilted zinc oxide and aluminum nitride thin film Field and temperature dependent parameters of the dc field induced resonances in Ba x Sr 1 − x Ti O 3 -based tunable thin film bulk acoustic resonatorsIn this article, the authors describe a novel fabrication technique of ZnO-based film bulk acoustic resonator ͑FBAR͒ devices using a new type of multilayered Bragg reflector with very thin chromium ͑Cr͒ layers additionally formed between silicon dioxide ͑SiO 2 ͒ and tungsten ͑W͒ layers. Each Cr layer is considered to enhance the adhesion between the SiO 2 and W layers. The fabricated FBAR devices are shown to operate at the frequency range of 2.7-3.0 GHz, along with good return loss as well as high Q factors. Furthermore, various thermal treatments are performed to further improve the resonant characteristics of the FBAR devices, and also their effects on the device characteristics are investigated. At the second-order resonant frequency, excellent resonant characteristics are observed in terms of high return loss and good figure of merit. This feasibility study indicates that the novel fabrication technique can be useful for future broadband mobile worldwide interoperability for microwave access applications.

show abstract

“…And the FBAR devices fabricated on S1, S2, and S3 samples resulted in the resonance frequency of 2.9, 3.0, and 2.7 GHz, respectively. Reportedly in references [4] and [7], the quality of BR may have an impact on the FBAR device characteristics. In the as-deposited W/SiO 2 multilayer, some physical imperfections like micro-defects may exist in the film microstructures, and some imperfect adhesions at interfaces remain between the physically deposited films, thus degrading the device performances.…”

Section: Introductionmentioning

confidence: 99%

“…Planar Luneburg lenses have been previously considered for use in wide angle scanning antenna [1][2][3][4]. Traditionally, the lens gradient refractive index is realized by using discrete layers of material of different refractive index or contoured dielectric filled parallelplate waveguide [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…Here many thousands of tiny metal posts with different heights were machined to effect local changes in dielectric constant hence refractive index grading. In [4] a lens composed of a dielectric filled planar parallel-plate operating in the TEM mode was described. This time the dielectric gradation was achieved by a combination of circular and triangular dispersed equivalent volume-averaged relative permittivity control as well as transverse resonance guided permittivity thickness control.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A novel fabrication technique of FBAR devices for mobile broadband WiMAX applications

Mai¹,

Lee²,

Pham³

et al. 2007

Micro & Optical Tech Letters

Self Cite

View full text Add to dashboard Cite

coplanar-square-patch dimensions can also be obtained for the proposed antenna at a fixed frequency.The calculated and/or measured the CSPA antenna radiation patterns at 1610 MHz, are shown in Figure 5. Good broadside radiation patterns are obtained. It is shown that the measured radiation patterns agree well with the computed results. The backward radiation pattern is less than Ϫ13 dB. These backward radiation patterns cause differences in gains. The gain and radiation efficiency vs. frequency characteristics of the CSPA antenna are illustrated in Figure 6.The measured antenna gain for frequencies within the CP bandwidth is about 3.7-3.9 dBi, and the radiation efficiency become close to 85%. SOME CONCLUSIONSA broadband CP-polarized coplanar-square-patch antenna operated in the 1550-MHz frequency band with a compact structure has been proposed and experimentally studied. The proposed antenna has impedance bandwidths of about 17.6% and the maximum return loss over 36 dB or 1.3:1 VSWR. It should be noted that the feed network design described here is not the unique solution for the proposed antenna, however, it provides good results.Good agreement between calculated and measured results is observed, so it means that the Zeland Software IE3D simulation code was helpful in designing the proposed antenna. On the other hand, ring-shaped microstrip antennas provide a good compromise between size reduction and antenna characteristics. For example, a square-ring antenna is one of the smallest circularly polarized microstrip antenna with size /4 ϫ /4. The characteristics of conformal-square-patch antenna can be controlled by means of dimension L 2 and slot width W. Use of the notch in the patch removed the necessity to provide orthogonally-phased feedlines beneath the patch and so reduced the component complexity significantly. The coplanar-patch antenna has an advantage over microstrip patches because of the screened feed which prevents spurious radiation. Higher order mode fields can be excited that are both circularly polarized and conical in shape.The proposed antenna would be very suitable for satellite communication systems applications operating in the L-band with CP, like: GPS, Iridium, Inmaresat, etc. ABSTRACT:In this study, we present a novel fabrication technique of FBAR devices as a feasibility study for mobile broadband WiMAX applications. This novel technique features the formation of very thin-film Cr adhesion layers between W and SiO 2 film layers in the Bragg reflectors, particularly to enhance the adhesion in-between. As a result, the resonances were found to occur at 2.7-3.0 GHz. In addition, excellent resonance characteristics were achieved in terms of return loss and Q-factor. This finding indicates that the proposed fabrication technique can be useful for the future mobile WiMAX applications.ABSTRACT: A printed Luneburg lens whose permittivity distribution is controlled by photo lithographically etching holes of different sizes into one side of a PCB ground plane is reported. The lens designed to oper...

show abstract

Significant resonance characteristic improvements by combined use of thermal annealing and Co electrode in ZnO-based FBARs

Cited by 13 publications

References 4 publications

ZnO-Based Film Bulk Acoustic Resonator Devices Feasible for Worldwide Interoperability for Microwave Access Applications

ZnO-Based Film Bulk Acoustic Resonator Devices Feasible for Worldwide Interoperability for Microwave Access Applications

Second-order resonant ZnO-based film bulk acoustic resonator devices and thermal techniques to improve their resonant characteristics

A novel fabrication technique of FBAR devices for mobile broadband WiMAX applications

Contact Info

Product

Resources

About