• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1095-1098
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• 2004

In this study, $Bi_2O_3-B_2O_3-ZnO$ glass system, which was expected to have similar properties with PbO containing glass system, was selected as a PbO replaceable potential composition because the atomic weight and ionic radius of Bi is similar to those of Pb. Glasses with different modifier/former ratio were prepared by melting the raw ingredient mixtures in $Bi_2O_3-B_2O_3-ZnO$ system, and the thermal and electrical properties of the sintered samples were examined. The glass transition temperatures and the dielectric constant of the glass pellets were between 350 $^{\circ}C{\sim}$500 $^{\circ}C$ and 15-35, respectively.

• Journal of the Korean Ceramic Society
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• v.30 no.2
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• pp.107-114
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• 1993

Zinc-Borosilicate(ZnO 65.0wt%, B2O3 21.5wt%, SiO2 9.0wt%, PbO or tiO2 4wt%) passivation glasses were studied using differential thermal analysis(DTA), scanning electron microscopy(SEM) observations, X-ray diffraction (XRD) patterns and measurement of thermal expansion coefficients. Passivation glasses containing 4wt% TiO2 and 4wt% PbO had crystallization temperature of 680~73$0^{\circ}C$ and major crystalline phases were identified by X-ray diffraction as $\alpha$-ZnO.B2O3 and $\alpha$-5ZnO.2B2O3. As increasing firing temperature, the size of crystalline phases increased by observation of SEM. The thermal expansion coefficient of crystallized glass frits was smaller than that of unfired glass.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.216-217
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• 2008

Zinc-oxide films were deposited by pulsed laser deposition (PLD) technique using doped ZnO target (mixed $In_2O_3$ 0.1, 0.3, 0.6 at. % - atomic percentage) on the p-type Si(111) substrate. A little Indium has added at the n-ZnO films for the electron concentration control and enhanced the electrical properties. Also, post thermal annealed ZnO films are shown an enhanced structural and controled electron concentration by the annealing condition for the hetero junction diode of a better emitting characteristics. The electrical and the diode characteristics of the ZnO films were investigated by using Hall effect measurement and current-voltage measurement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.30-36
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• 2002

The effects of the sintering additives such as B $i_2$ $O_3$ and $V_2$ $O_{5}$ on the microwave dielectric and sintering properties of ZnTi $O_3$ system were investigated. Highly dense samples were obtained for ZnTi $O_3$ at the sintering temperature range of 870~90$0^{\circ}C$ with B $i_2$ $O_3$ and $V_2$ $O_{5}$ additions of <1 wt.%, respectively. The microwave dielectric properties of ZnTi $O_3$ with 0.6 wt.% B $i_2$ $O_3$ and 0.5 wt.% $V_2$ $O_{5}$ were as follows: Qx $f_{o}$ = 48,400 GHz, $\varepsilon$$_{r}$= 22, and $\tau$$_{f}$ = -43 ppm/$^{\circ}C$. In order to improve temperature coefficient of resonant frequency, Ti $O_2$ was added to the abode system. The optimum amount of Ti $O_2$was 15 mol.% when sintered at 87$0^{\circ}C$, at which Ive could obtain following results: Qx $f_{O}$ = 44,700GHz, $\varepsilon$$_{r}$ = 26, and $\tau$$_{f}$ = 0 PPm/$^{\circ}C$.>.EX>.>.>.EX>.>.>.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.10
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• pp.831-835
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• 2014

The relative concentration of surface and interfacial defects in hydrothermally grown ZnO nanostructures was investigated by a comparison of two samples having different growth temperatures via bias voltage sweep rate under laser illumination of 405 and 355 nm. The current of small ZnO nanostructures (growth temperature of $75^{\circ}C$) decreased when induced more slowly bias voltage sweep rate under the laser illumination. In contrast, the current of large ZnO nanostructures (growth temperature of $90^{\circ}C$) increased. This difference in currents indicates the relation of relative defects concentration between surface and interfacial defects of ZnO nanostructure. Our experimental approach has potential applicability in the analysis of influence on defects in ZnO devices.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.15-19
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• 2003

In This paper, we developed 1.96 GHz air gap type FBAR BPF using ZnO as piezoelectric sputtered by RF magnetron at room temperature. FBAR BPF was fabricated by sputtering bottom electrode (Al), ZnO as piezoelectric and top electrode (Mo) on Si wafer one by one with RF magnetron sputter, then Si was dry etched to make an air hole. XRD test result of fabricated FBAR BPF showed that ZnO crystal was well pre-oriented as (002) and sigma value of XRC was 1.018. IL(Insertion loss) showed excellent result as 1 dB.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.141-144
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• 2003

This study proposes ZnO thin film as a piezoelectric material for SAW (surface acoustic wave) filter. The ZnO thin film with thickness $2.6{\mu}m$ was deposited (0001)-oriented sapphire by RF magnetron sputtering technique. IDTs (inter-digital transducers) electrodes were patterned upon SAW filter mask with solid finger structure unapodized using lift-off method on ZnO piezoelectric thin film. SAW propagation velocity was measured with the center frequency by HP 8753C network analyzer. A fabricated ZnO SAW filter exhibited a high propagation velocity of 5433 $^m/s$ and relatively insertion loss of -53.391dB at $\lambda=80{\mu}m$. The side-lobe attenuation of the center frequency was about 17dB. When the wavelength was $80{\mu}m$ $(\lambda/4=20{\mu}m)$, the center frequency was 67.907 MHz. $k^2$ (electromechanical coupling coefficient) was 15.84 %.

• Journal of the Korean Ceramic Society
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• v.43 no.9 s.292
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• pp.527-531
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• 2006

In order to study the influence of post-annealing treatment on the frequency characteristics of the Li doped ZnO(Li:ZnO) FBAR(Film Bulk Acoustic Resonator) device, we investigated the material and electrical properties of Li:ZnO films in the annealing temperature range from 300 to $500^{\circ}C$. In our samples, as annealing temperature was increased, Li:ZnO films showed the improvement of high c-axis orientation and resistance value with relieved stress and low surface roughness. In addition to, the return loss in the frequency property of fabricated FBAR was improved by annealing treatment from 24.9 to 29.8dB. From experimental results, the optimum post-annealing temperature for FBAR is $500^{\circ}C$ and it can obtain excellent Li:ZnO FBAR performance with stronger c-axis orientation, smoother surface, relieved stress, and lower loss factor.

• Journal of the Korean Vacuum Society
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• v.22 no.1
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• pp.20-25
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• 2013

ZnO:Al thin films deposited by RF magnetron sputtering were post-annealed and the electrical and optical properties of ZnO:Al thin films were investigated before and after anneling. We confirmed that the ZnO:Al thin film was affected by post-annealing temperature. As post-annealing temperature increases, crystallinity and transmittance in visible area (400~800 nm) of ZnO:Al thin films decreased. While sheet resistance of thin films increased sharply with increasing to $400^{\circ}C$. This result is due to reduce of carrier concentration caused by absorption of $O_2$ or $N_2$ at surface of thin film.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.12
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• pp.1219-1227
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• 2014

For development of the surface acoustic wave bandpass filter(SAW-BPF), we fabricated the high quality ZnO thin films through the step-by-step(double) deposition using two different deposition methods which are pulsed laser deposition(PLD) and RF sputtering techniques. The second growth of ZnO thin films was completed by RF sputtering method on the first ZnO thin films pre-deposited by PLD method. The characteristics of ZnO thin films were analyzed by XRD, SEM and AFM systems. The FWHM of ${\omega}$-scan analysis and the minimum RMS value of surface roughness of step-by-step grown ZnO thin films were $0.79^{\circ}$ and 1.108 nm respectively. As a result, the crystallinity and the preferred orientation of the grown ZnO thin films were kept good quality and the surface roughnesses of those were improved by post-annealing process as comparison with ZnO thin film fabricated by the conventional PLD technique only. Using these proposed ZnO thin films, we demonstrated the RF device such as SAW-BPF, built by the proposed ZnO thin films, shows that it has the bandwidth of 2.98 MHz and the insertion loss of 36.5 dB at the center frequency of 260.8 MHz, respectively.