Tae-Yong Lee

Properties of the Various Power Ratio in GZOB/AU Multilayers

We investigated the effects of power ratio on the electrical and optical properties of Au based Ga-, B- codoped ZnO(GZOB) thin films. GZOB thin films were deposited on Au based poly carbonate(PC) substrate with various power in the range from 60 to 120 W by DC magnetron sputtering. In the result, GZOB films at 100 W exhibited a low resistivity value of , and a visible transmission of 80 % with a thickness of 300 nm. This result indicated that the addition of Ga and B in ZnO films leads to the improvement of conductivity and transparent. From the result, we can confirm the possibility of the application as transparent conductive electrodes.

The Characteristics of Ga-doped ZnO Transparent Thin Films by using Multilayer

With development of electronic products the demands for miniaturization and weight-lightening have increased until a recent date. Accordingly, The effort to substitute glass substrates was widely made. However, polymer substrates have weak point that substrates were damaged at high temperature. In this paper, we deposited transparent conductive film at low temperature. And we inserted Au thin film between oxide to compensate for deteriorated electrical characteristics. Ga-doped ZnO(GZO) multilayer coatings were deposited on glass substrate by DC sputtering. The optimization of deposition conditions of both AZO and Au layers were performed to obtain better electrical and optical characteristics in advance. We presumed that the properties of multilayer were affected by the deposition process of both GZO and Au layers. The best multilayer coating exhibited the resistivity of and transmittance of 77 %. From these results, we can confirm a possibility of the application as transparent conductive electrodes.

Study of Effect of PZT Thin Film Prepared in Different Post-Annealing Temperature Using SIMS

The effect of various post-annealing temperature to sputtered Pb(Zr,Ti) (PZT) thin films was investigated. The crystallization process, surface morphology and the electrical characteristics strongly depends on the rapid thermal annealing (RTA). In radio frequency (RF) sputtering methods, there were many papers mostly forcing on the crystal forming and the surface variations with different elements distribution (Pb, Ti, Zr, O) on the surface of the PZT layer. In this experiment, the post-annealing treatment promoted the Pb volatilization in PZT thin film and affected the Ti diffused throughout the Pt layer into the PZT layer. Second ion mass spectroscopy (SIMS) analysis was employed to show that the Pb element in the PZT layer was decreased at the same time the Ti element mass was slight decreased than Pb with increasing RTA temperature. That result prove the content of Pb affect the PZT thin film property.

Effects of Sputtering Condition on Structural Properties of PZT Thin Films on LTCC Substrate by RF Magnetron Sputtering

Recently, low temperature co-fired ceramic (LTCC) technology is widely used in sensors, actuators and microsystems fields because of its very good electrical and mechanical properties, high reliability and stability as well as possibility of making 3D micro structures. In this study, we investigated the effects of sputtering gas ratio and annealing temperature on the crystal structure of (PZT) thin films deposited on LTCC substrate. The LTCC substrate with thickness of were fabricated by laminating 4 green tapes which consist of alumina and glass particle in an organic binder. The PZT thin films were deposited on Pt / Ti / LTCC substrates by RF magnetron sputtering method. The results showed that the crystallization of the films were enhanced as increasing mixing ratio. At about 25% mixing ratio, was well crystallized in the perovskite structure. PZT thin films was annealed at various temperatures. When the annealing temperature is lower, the PZT thin films become a phyrochlore phase. However, when the annealing temperature is higher than , the PZT thin films become a perovskite phase. At the annealing temperature of , perovskite PZT thin films with good quality structure was obtained.

A Study on Efficiency of Energy Conversion for a Piezoelectric Power Harvesting Using Polyvinylidene Fluorid Film

Piezoelectric materials can be used to convert mechanical energy into electrical energy. In this study, we investigated the possibility of harvesting from mechanical vibration force using a high efficient piezoelectric material-polyvinylidene fluoride (PVDF). A piezoelectric energy harvesting system consists of rectifier, filter capacitor, resistance. The experiments were carried out with impacting force to PVDF film with the thickness of 1 . The output power was measured with change in the load resistance value from 100 to 2.2 . The highest power was obtained under optimization by selection of suitable resistive load and capacitance. A power of 0.3082 was generated at the external vibration force of 5 N (10 Hz) across a 1 optimal resistor. Also, the maximum power of 0.345 was generated at 22 and 1 . The developed system was expected at a solution to overcome the critical problem of making up small size energy harvester.

The Characteristics of GZOB Thin Film on O 2 Plasma Treated Polymer Substrate

We investigated the effects of a high density plasma treatment on the structural and electrical properties of Ga-, B- codoped ZnO (GZOB) films. The GZOB films were deposited on polymer substrate without substrate heating by DC magnetron sputtering. Prior to the GZOB film growth, we treated a polymer substrate with highly dense inductively coupled oxygen plasma. The optical transmittance of the GZOB film, about 80 %, was maintained regardless of the plasma pre-treatment. The resistivity of the GZOB film on PC substrate decreased from 9.08 without an plasma pre-treatment to 2.12 with an plasma pre-treatment. And PES substrate decreased from 1.14 without an plasma pre-treatment to 6.13 with an plasma pre-treatment.

The Preferred Orientation and Morphology Characteristics of AlN Thin Films Prepared by RF Power Under Room Temperature Process

In this paper, we investigated the (002) preferred orientation and morphology characteristics of AlN thin film by using reactive rf sputtering. Additionally, AlN thin films grown in the range from 150 to 300 W were studied under room temperature without substrate heating and post annealing. Sputtered AlN thin films were well grown on Si substrates and the (002) main peak in XRD patterns showed the highest intensity at 300 W with degree of full width at half-maximum (FWHM). As increased RF power, the surface roughness was increased from 1.0 to 3.4 nm. In Fourier transformation infrared spectroscopy (FTIR), (TO) and (TO) mode closed to AlN thin film confirmed the changes with increasing the intensity rate. From these results, we could confirm a chance of the growth of AlN thin film by only low temperature.

Fabrication of Li 2 CO 3 -doped Thin Film Bulk Acoustic Resonator and Structural, Electrical Properties as a Function of Annealing Temperatures

In this study, we fabricated FBAR(film bulk acoustic resonator) by using as a function of annealing temperature and concentrated on effect of frequency characteristic of FBAR. The results show that the annealing affects resistivity and crystallity. The optimum properties were observed for film annealed at . The resistivity was and the roughness was 21.10 nm. And the return loss is improved from -24.9 at to -29.8 at without the resonant frequency change. We finally confirmed the improvement on the frequency characteristics of FBAR device by annealing process at the optimized condition.

Effect of Annealing on the Structural, Electrical and Optical Characteristics of Ga-doped ZnO(GZO)films

In this study we present the effect of annealing temperatures on the structural, electrical and optical characteristics of Ga-doped ZnO (GZO) films. GZO target is deposited on coming 7059 glass substrates by DC sputtering. and then GZO films are annealed at temperatures of 400, 500, in air ambient for 20 min. in this case of as-grown film, it shows the resistivity of and transmittance under 85%, whereas the electrical and optical properties of film annealed at are enhanced up to and 90%, respectively.

Dependences of Various Substrate Temperature on the Structural and Electrical Properties of ZnO Thin Films deposited by RF Magnetron Sputtering

In this study we investigated the variation of the substrate temperatures using RF sputtering to identify the effect on the structure and electrical properties by c-axis orientation of ZnO thin film. ZnO thin films were prepared on Al/Si substrate. In our experimental results, ZnO thin film at was well grown with (002) peak of ZnO thin film, the thin film showed the high resistivity with the value of and the roughness with 27.06 nm. As increased the substrate temperatures, the grain size of ZnO thin films was increased. From these results, we could confirm the suitable substrate temperature of ZnO thin films for FBAR(film bulk acoustic resonator).