Sung-Bo Heo

Effect of Annealing in a Nitrogen Atmosphere on the Properties of In 2 O 3 Films Deposited with RF Magnetron Sputtering

In2O3 films were deposited by RF magnetron sputtering on a glass substrate and then the effect of post depositionannealing in nitrogen atmosphere on the structural, optical and electrical properties of the films was investigated. Afterdeposition, the annealing process was conducted for 30 minutes at 200 and 400oC. XRD pattern analysis showed that the asdeposited films were amorphous. When the annealing temperature reached 200-400oC, the intensities of the In2O3 (222) majorpeak increased and the full width at half maximum (FWHM) of the In2O3 (222) peak decreased due to the crystallization. Thefilms annealed at 400oC showed a grain size of 28nm, which was larger than that of the as deposited amorphous films. Theoptical transmittance in the visible wavelength region also increased, while the electrical sheet resistance decreased. In this study,the films annealed at 400oC showed the highest optical transmittance of 76% and also showed the lowest sheet resistance of89Ω/□. The figure of merit reached a maximum of 7.2×10−4Ω−1 for the films annealed at 400oC. The effect of the annealingon the work-function of In2O3 films was considered. The work-function obtained from annealed films at 400oC was 7.0eV. Thus,the annealed In2O3 films are an alternative to ITO films for use as transparent anodes in OLEDs.

Effect of Intermediate Metal on the Methanol Gas Sensitivity of ITO Thin Films

ITO thin films and gold (Au), copper (Cu) and nickel (Ni) intermediate ITO multilayer (ITO/Au/ITO, ITO/Cu/ITO, ITO/Ni/ITO) films were deposited on glass substrates with a reactive radio frequency and direct current magnetron sputtering system and then the effect of intermediate metal layer and annealing temperature on the methanol gas sensitivity of ITO films were investigated. Although both ITO and ITO/metal/ITO (IMI) film sensors have the same total thickness of 100 ㎚, IMI sensors have a sandwich structure of ITO 50 ㎚/metal 10 ㎚/ITO 40 ㎚. The change in the gas sensitivity of the film sensors caused by methanol gas ranging from 100 to 1000 ppm was measured at room temperature. The IAI film sensors showed the higher sensitivity than the other sensors. Finally, it is concluded that the ITO 50/Au 10/ITO 40 ㎚ film sensors hasthe potential to be used as improved methanol gas sensor.

Deposition Characteristics of TiO 2 Thin Films Prepared by DC Pulsed Magnetron Sputtering

This study reports a fabrication of TiO2 on the surface of dental implants by pulsed d.c. magnetron sputtering from a Ti target. A systematic investigation on the microstructure and mechanical properties of TiO2 films was carried out with the variation of O2 contents and substrate temperatures. The effects of deposition parameters on the fabricated structures were investigated by X-ray diffraction (XRD) technique and field emission scanning electron microscope (FE-SEM). Hydrophilic properties were evaluated by measuring water contact angles on the film surface. With increasing O2 contents up to 40%, surface roughness of TiO2 film increased while relatively smooth surface was obtained with 50% O2 contents. Surface roughness and adhesion strength both increased as substrate temperature increased up to 200°C. From these results, hydrophilic and adhesive properties of the present TiO2 films synthesized with 40% O2 at 200°C are regarded to be suitable for biocompatible applications.

Effect of Vacuum Annealing on the Properties of ITO Thin Films

Abstrart ITO thin films deposited on glass substrate with RF magnetron sputtering were vacuum annealed at 100, 200 and 300C for 30 minutes and then effect of annealing temperature on the structural, electrical and optical properties of ITO films were investigated. The structural properties are strongly related to annealing temperature. The annealed films above 100C are grown as a hexagonal wurtzite phase and the largest grain size is observed in the films annealed at 300C. The electrical resistivity also decreases as low as 4.65 × 10 Ωcm with a increase in annealing temperature and ITO film annealed at 300C shows the lowest sheet resistance of 43.6 Ω/ □ . The optical transmittance in a visible wavelength region also depends on the annealing temperature. The films annealed at 300C show higher transmittance of 80.6% than those of the films prepared in this study. (Received January 28, 2013; Revised February 13, 2013; Accepted February 20, 2013)