Min J. Jung

Atmospheric RF plasma effects on the film adhesion property

Abstract Commercial polymers in thin film form were used for modification by atmospheric RF plasma. The influence of the plasma treatments using Ar and Ar+O 2 on surface energy, morphology and chemical structure of the films was investigated. It was revealed that both modifications caused surface activation of the polymer film, but they obeyed different mechanisms enhancing polymer wettability. First, surface graphitization due to argon sputtering caused hydrogen to free the surface and then reacts with oxygen in the air. Second, surface oxidation is connected with the functional group formation. The reactions of Ti with the polymer led to the simultaneous formation of TiCl 2 , TiC, Ti-oxide and they contributed to film adhesion. In comparison with Ar, the mixed Ar+O 2 RF plasma treatment was a more timesaving process and had more influences on surface activation and film adhesion.

Deposition of Ti thin film using the magnetron sputtering method

This paper presents a modification to conventional magnetron sputtering systems. The introduction of a grid in front of the target increases the metal ion ratio. Using OES and observing both Ti neutrals and ions, it was confirmed that the relative ionization could be qualitatively extended with grid-attached magnetron sputtering compared with a conventional magnetron system. On the other hand, the relative ionization of Ar decreased. Our results also show that the Ti films deposited by conventional magnetron exhibit (100) preferred orientation as the bias voltage increased. On the other hand, in the case of the grid-attached magnetron, the Ti films exhibit highly preferred (002) orientation with increasing bias voltage. The experiments clearly demonstrated that a dense Ti film with a smooth, specular reflecting surface can be produced using the grid-attached magnetron with increased Ti ion flux compared to the conventional magnetron.

Surface modification effects on film growth with atmospheric Ar/Ar+O2 plasma

Abstract Commercial, purified PVC films were surface-modified by Ar and mixed Ar+O2 RF plasma at atmospheric pressure. The change of surface properties was monitored by contact angle measurements. Both modifications cause surface oxidation of PVC films, which is connected with the formation of functional groups enhancing polymer wettability. This process is very fast and efficient in mixed Ar+O2 RF plasma but relatively slower during PVC exposure to Ar. The interface reactions of sputtered Ti with PVC have been studied using high resolution X-ray diffractometer and X-ray photoelectron spectroscopy. The reactions of Ti with PVC lead to the simultaneous formation of TiCl2, TiC and Ti-oxide.

Polycrystalline Si thin film growth on glass using pulsed d.c. magnetron sputtering

Crystalline poly-Si thin films were deposited on Corning glass substrates at a temperature of 500 °C using a pulsed d.c. magnetron sputtering source. The increased bias voltage causes an enhancement of the potential difference between the plasma and substrate. In case of the bipolar pulsed d.c. magnetron sputtering, Vp shows higher value than that in the unipolar pulsed d.c. as the bias voltage increases. Therefore, the mobility of the sputtered adatoms increases by the surface heat accumulation of energetic sputtered particles with the increased bias voltage. Consequently, more higher mobility (41 cm2 Vs−1) and crystallinity were obtained for the Si film grown with the bipolar-pulsed d.c. magnetron sputtering due to the energy incorporation by enhanced bombardment of Ar ions.

Deposition of TiOx thin film using the grid-assisting magnetron sputtering

This paper presents a modification to conventional magnetron sputtering systems. The introduction of a grid in front of the target increases metal ion ratio in the plasma. By using optical emission spectroscopy (OES) and observing both Ti neutral and Ti ion, the relative ionization could be qualitatively extended to grid-attached magnetron sputtering as compared with conventional magnetron systems. Experiments clearly demonstrate microstructural cross-sectional TEM analysis of the titanium oxide film changes from a columnar-like (anisostropic) structure to a homogenous structure (isotropic), and resulting in a high refractive index. It is believed that more energetic ion bombardment induced the structural changes in films in the case of grid-assisted magnetron sputtering.

Mechanical properties of Ti-Me-N coated polymer

Summary form only given, as follows. Summary form only given. Polymers frequently replace traditional engineering materials such as metals, glasses and ceramics. The utilization of polymers can further be enhanced by coating them by a protective layers, optical coatings, gas permeation barriers, and others. However, the desirable bulk properties of polymers are often compromised by unfavourable surface characteristics, such as low hardness, low resistance to abrasion and scratching, and low surface energy, that generally leads to poor adhesion. In our previous work, we synthesized Ti-Cu-N and Ti-Ag-N nano-composite films with various Cu and Ag contents. The hardness of Ti-Cu-N and Ti-Ag-N films could be significantly improved by addition of Cu and Ag, indicating that an appropriate amount of doping element was selected. The maximum hardness of these films reached to about 40GPa and friction coefficient was about 0.3 In our study, to overcome the film adhesion problem, we used a pretreatment of a polymer by atmospheric RF plasma After pretreatment, we have deposited Ti-Me-N, nano-composite films on polymer by magnetron sputtering. To analysis of atmospheric plasma and metal doping effect on plasma, we measured plasma states by Optical Emission Spectroscopy (OES) and Residual Gas Analyzer (RGA). The deposition rate, microstructure, surface morphology of the films were studied using /spl alpha/-step profilometer, High Resolution X-Ray Diffraction(HRXRD), Transmission Electron Microscopy(TEM) and Atomic Force Microscope(AFM). The mechanical properties of metal doped transition metal nitride films were evaluated by nano-indentation test.