Jin Kon Kim

DRY ETCHING OF SnO2 AND ZnO FILMS IN HALOGEN-BASED INDUCTIVELY COUPLED PLASMAS

High density plasma etching of SnO2 and ZnO films was performed in chlorine- (Cl2/Ar and BCl3/Ar) and fluorine-based (CF4/Ar and SF6/Ar) inductively coupled plasmas. The etch process window for fabricating metal oxide nanowires with high aspect ratios including high and controllable etch rates, high etch selectivities to mask material and high anisotropy was established. Maximum etch rates of ~2050 A/minute (BCl3/Ar) and ~1950 A/minute (SF6/Ar) for ZnO, and ~1950 A/minute (Cl2/Ar) and ~2000 A/minute (SF6/Ar) for SnO2 were obtained. Ni was found to provide very high etch selectivities with maximum values of ~67 to SnO2 and ~17 to ZnO, respectively.

ELECTRICAL, TRANSPARENCE AND WETTING PROPERTIES OF DIAMOND LIKE CARBON FILMS

In this study, we have developed the method for obtaining a conductive DLC layer on glass substrate of 30×30mm size by adding Nitrogen or Silane gas during CVD(Chemical Vapor Deposition) growth. The growth rate and electrical conductivity were investigated under different plasma deposition condition. In addition, we measured the optical transmittance spectra of the films. From the measurements of optical transmittance in range of 300 to 1150 nm wavelength, an optical transmittance is obtained from 80% to 90% from the DLC films grown with lower gas flow rates. The characteristic of DLC films were evaluated by various techniques including alpha step surface profiler, micro Raman spectroscope, X-ray diffraction(XRD) and Nano- indentation.

The Effect of Precursor Composition on the Structural Properties of Nanocrystalline Diamond Films

Nanocrystalline diamond (NCD) films were grown by hot filament CVD and the precursor composition dependence of the structural properties was examined. Films grown at 1 and 2 CH4 Vol% were found to be NCD layers with grain sizes of ~23-25 nm while films grown at 3-5 Vol% were identified as the mixtures of microcrystalline diamond and graphitic phase. The sp2/sp3 bonded carbon ratio in the grown films increased as the CH4 content increased up to 3 Vol% and then decreased beyond 4 Vol%. Microstructure and deposition rate were also found to be affected by the precursor composition and the NCD film grown at 1 CH4 Vol% showed a very dense microstructure and the highest deposition rate of ~3 nm/min.

High density plasma etching of ultrananocrystalline diamond films in O2/CF4 and O2/SF6 inductively coupled plasmas

Inductively coupled plasma etching of ultrananocrystalline diamond (UNCD) films was performed in O2/CF4 and O2/SF6 discharges. Higher etch rates were produced for the O2/SF6 discharges and the films etched in the 10O2/5CF4 discharges retained smooth surface morphology similar to the unetched control sample. Al mask showed a good etch selectivity to the UNCD for both plasma chemistries and highly anisotropic pattern transfer with a vertical sidewall profile was achieved.

The study and fabrication of DLC micropattern on roll mold

Diamond-like carbon (DLC) coating is becoming a promising protective coating layers due to its superior properties. In this study, instead of protective coating, DLC film was applied as the only component for micropattern then etched with lithography and lift-off process selectively. Furthermore, DLC film has been fabricated on aluminum roll mold. Then UV curing resin was applied to form the pattern on the polyethylene terephthalate (PET) film. The dimension and formation of the DLC micropattern on roll mold were analyzed. Moreover, the Raman spectroscopic of nitrogen-doped DLC film was analyzed.

Effects of oxygen partial pressure on the properties of indium tin oxide film on PET substrates by RF magnetron sputtering

Indium tin oxide (ITO) films with various oxygen partial pressure from 0 to 6 × 10 Pa were prepared onto polyethylene terephthalate (PET) using RF magnetron sputtering at room temperature. The structural, electrical and optical properties of the grown ITO films were investigated as a function of the oxygen partial pressure. The amorphous nature of the ITO films was dominant at the partial pressure below 1 × 10 Pa and the degree of crystallinity increased as the oxygen concentration increased further. This structural change comes with the increased carrier concentration and reduction of the electrical resistivity down to 9.8 × 10 Ω · cm. The average transmittance (at 400~800 nm) of the ITO deposited on the PET substrates increased as the oxygen partial pressure increased and transmittance above 80 % was achieved with the partial pressure of 4 × 10 Pa. The results show that the choice of optimal oxygen partial pressure can present improved film crystallinity, the increased carrier concentration, and the enhancement in the electrical conductivity.

Enhanced Diamond Nucleation by Surface Texturing of Si Substrate in SF6/O2 Plasmas

SF6/O2 plasma surface texturing was employed to pretreat Si substrate for achieving enhanced diamond nucleation density. Surface roughness of the textured Si was found to be strongly dependent on the process pressure and normalized roughness values in the range of 2-16 were obtained. Remarkably enhanced nucleation densities of ~1010 cm-2 compared to conventional mechanical abrasion were obtained after seeding for the surface textured Si substrates. Raman spectroscopy revealed that ultrananocrystalline diamond films with grain size below 10 nm were grown on the surface textured Si.