Preparation of Metal-Containing Diamond-Like Carbon Films by Magnetron Sputtering and Plasma Source Ion Implantation and Their Properties

Metal-containing diamond-like carbon (Me-DLC) films were prepared by a combination of plasma source ion implantation (PSII) and reactive magnetron sputtering. Two metals were used that differ in their tendency to form carbide and possess a different sputter yield, that is, Cu with a relatively high sputter yield and Ti with a comparatively low one. The DLC film preparation was based on the hydrocarbon gas ethylene (C2H4). The preparation technique is described and the parameters influencing the metal content within the film are discussed. Film properties that are changed by the metal addition, such as structure, electrical resistivity, and friction coefficient, were evaluated and compared with those of pure DLC films as well as with literature values for Me-DLC films prepared with a different hydrocarbon gas or containing other metals

Surface Structuring of Diamond-Like Carbon Films by Chemical Etching of Zinc Inclusions

A diamond-like carbon (DLC) film with a nanostructured surface can be produced in a two-step process. At first, a metal-containing DLC film is deposited. Here, the combination of plasma source ion implantation using a hydrocarbon gas and magnetron sputtering of a zinc target was used. Next, the metal particles within the surface are dissolved by an etchant (HNO₃:H₂O solution in this case). Since Zn particles in the surface of Zn-DLC films have a diameter of 100–200 nm, the resulting surface structures possess the same dimensions, thus covering a range that is accessible neither by mask deposition techniques nor by etching of other metal-containing DLC films, such as Cu-DLC. The surface morphology of the etched Zn-DLC films depends on the initial metal content of the film. With a low zinc concentration of about 10 at.%, separate holes are produced within the surface. Higher zinc concentrations (40 at.% or above) lead to a surface with an intrinsic roughness

Properties of Hydrogenated DLC Films as Prepared by a Combined Method of Plasma Source Ion Implantation and Unbalanced Magnetron Sputtering

Unbalanced magnetron sputtering (UBMS) is suitable for the preparation of hard and hydrogen-free diamond-like carbon (DLC) films. Since those films generally suffer from internal stresses and bad adhesion, the addition of a methane source offers two advantages: (i) the control of the film properties by variation of the hydrogen content and (ii) a pretreatment of methane plasma source ion implantation (PSII), which results in a gradient carbon layer within the substrates, ensuring the adhesion of the subsequently deposited DLC films. PSII and UBMS were combined to prepare DLC films on stainless steel substrates and silicon wafers. Different amounts of methane were added to the working gas, argon, to investigate the effect of the hydrogen content on the film properties, i.e., hardness, adhesion, and friction coefficient. Composition and chemical structure of the films were investigated by depth profiling (secondary-ion mass spectrometry) and Raman spectroscopy. Smooth adhesive films could be obtained with the lowest friction coefficient for small additions of methane as a hydrogen source during the sputtering process

Long-term thermal stability of Si-containing diamond-like carbon films prepared by plasma source ion implantation

The long-term stability of silicon-containing diamond-like carbon films was investigated. The samples were prepared by plasma source ion implantation with a mixture of tetramethylsilane (TMS) and acetylene (C2H2) using negative high voltage pulses. The film composition was changed by varying the flow rates of the TMS and C2H2 gases, resulting in a Si content from 0 to 44 at.%. After deposition the films were annealed at temperatures from 523 K to 773 K for 168 h in ambient air. The effect of the Si content on the structure, the mechanical and tribological properties of the DLC films was investigated. A silicon oxide layer is produced on the surface of the film which improves the thermal stability. Mechanical and friction characteristics of the Si-DLC were not much affected by the long-term thermal annealing if the temperature was kept below 573 K

Methane plasma-based ion implantation of metallic and galvanically oxidized tantalum

Tantalum and oxidized tantalum exhibit distinct differences when treated with plasma-based ion implantation of methane with − 20 kV. The implantation profiles of carbon are similar, but carbides are formed in the case of tantalum, as verified with X-ray diffraction and X-ray photoelectron spectrometry in combination with depth profiling, whereas there is no detectable carbide in the tantalum oxide film. The distributions of the co-implanted hydrogen also vary in that the intensity in depth profiling with secondary ion mass spectrometry does steadily decrease in the oxidized Ta, while in the metallic Ta it shows a short indentation below the surface and then decreases only very slowly

Deposition of Diamond-Like Carbon Films on Inner Wall Surfaces of Millimeter-Size-Diameter Steel Tubes by Plasma Source Ion Implantation

Diamond-like carbon (DLC) film deposition on the interior surfaces of steel tubes was carried out by plasma source ion implantation. SUS304 austenitic-type stainless steel tubes with inner diameters of 9, 5, and 4 mm were used as substrate tubes. Acetylene was the working gas for the plasma that was generated by applying a negative pulse voltage of $-$18 kV to the substrates. The surface morphology of the films and the film thickness were observed by atomic force microscopy and scanning electron microscopy. The composition within the film and at the interface was examined by depth profiling with Auger electron spectroscopy and secondary ion mass spectrometry. The film structure was characterized by Raman spectroscopy. The friction coefficient of the untreated substrate and the DLC films was evaluated by a reciprocating sliding test. The DLC film surfaces were smooth, and no special structure was observed on the surface. The DLC film thicknesses, structure, and composition on the interior surface of the steel tube depend, on the one hand, on the gas and pulse conditions and, on the other hand, on the distance from the end of the tube, as well as on the diameter of the tube. A low friction coefficient of 0.2 was derived for the deposited DLC films

Diamond-like carbon films formed by hydrocarbon plasma immersion ion implantation with methane/toluene mixtures

Plasma immersion ion implantation of silicon with methane, toluene and mixtures of both as plasma-foming gases gave films of amorphous carbon (a-C:H, or diamond-like carbon DLC) on a transition zone of silicon carbide, as shown by X-ray photoelectron spectrometry and Rutherford backscattering spectrometry. Toluene leads to faster DLC film growth than methane. Raman spectra showed the typical D- and G-bands of DLC, in case of toluene more distinct than for toluene. IR-spectroscopy gave indications of SiC and C–H bonds

Deposition of silicon-containing diamond-like carbon films by plasma-enhanced chemical vapour deposition

Silicon-containing diamond-like carbon (Si-DLC) films were prepared on silicon wafer substrates by DC glow discharge. Acetylene and mixture with tetramethylsilane gases were used as working gases for the plasma. A negative DC voltage was applied to the substrate holder. The DC voltage was changed in the range from − 1 kV to − 4 kV. The surface morphology of the films and the film thickness were observed by scanning electron microscopy. The compositions of the Si-containing DLC films were examined by X-ray photoelectron spectroscopy. The film structure was characterized by Raman spectroscopy. A ball-on-disc test with 2 N load was employed to obtain information about the friction properties and sliding wear resistance of the films. The films were annealed at 723 K, 773 K and 873 K in ambient air for 30 min in order to estimate the thermal stability of the DLC films. The surface roughness of the Si-containing DLC films was very low and no special structure was observed. The deposition rate increased linearly with Si content. The positions of D- and G-bands in Raman spectra decreased with Si content. The integrated intensity ratios ID/IG of the Si-containing DLC films decreased with Si content. A very low friction coefficient of 0.03 was obtained for a 24 at.% Si-containing DLC film. The heat resistivity of DLC films can be improved by Si addition into the DLC films

Comparison of the Surface Modification of Tungsten and Gold by Methane Plasma Source Ion Implantation

On the basis of two substrate materials which possess similar atomic mass but different physical and chemical properties (e.g., sputtering yield and susceptibility for carbide formation), the treatment effects of methane plasma source ion implantation are compared. Tungsten and gold underwent implantation by the use of high voltage pulses of $-$20 kV in a methane atmosphere of 1 Pa. Differences in the formed surface structure, in implantation layer thickness and lateral distribution of the implanted species, and in surface properties such as friction coefficient and hardness are analyzed. The dependence of the surface modifications on the treatment conditions and on the substrate properties is described