Yun M. Chung

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.

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.

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.

Comparative Study on Mechanical Properties of MoSiN Multilayer Films Deposited on Si(100) and Ti-covered Si(100) Substrates

We deposited MoSiN multilayer films using a MoSi2 target via pulsed-DC and radio-frequency (RF) magnetron sputtering methods. For the fabrication of the Ti-covered Si(100) substrate, we also grew Ti layers via the RF magnetron sputtering method. To improve the mechanical properties of the as-grown MoSiN thin films, argon and nitrogen plasmas ignited by RF and pulse DC under vacuum conditions were also used with a total pressure of 0.7 Pa, a substrate bias of −100 V, and a substrate ion current density of 1.5 mA/cm2. The as-grown MoSiN films were investigated for hardness (Gpa) and macro-stress(s) properties, and the relationship between film composition and micro-structures was analyzed using x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). The maximum hardness and stress values of the MoSiN films were 32 GPa and −2.5 GPa, respectively, depending on variations of substrates and reactive gas.

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.