Diamond-Like Carbon Films with Low Internal Stress by a Simple Bilayer Approach

Amorphous carbon films with a high hardness usually suffer from high internal stress. To deposit films with a hard top surface but reduced internal stress, a simple bilayer approach was used. Films were prepared by plasma source ion implantation, using only hydrocarbon precursors. The single layer with the highest hardness (deposited by a low direct current (DC) voltage and radio frequency (RF) generation of the plasma) has the highest internal stress with more than 3.5 GPa. By adding an interlayer with a lower hardness, the resulting stress of the bilayer film can be reduced to below 1.4 GPa while maintaining the high hardness of the top layer. By avoiding metallic interlayers or dopants within the films, the deposition process can be kept simple and cost-effective, and it is also suitable for three-dimensional samples.

The Influence of Preparation Conditions on the Structural Properties and Hardness of Diamond-Like Carbon Films, Prepared by Plasma Source Ion Implantation

Diamond-like carbon (DLC) films were prepared from a hydrocarbon precursor gas by plasma source ion implantation (PSII), in which the plasma generation and the film deposition were coupled; i.e., the plasma was generated by the applied voltage and no additional plasma source was used. Several experimental parameters of the PSII process were varied, including the sample bias (high voltage, DC or pulsed), gas pressure, sample holder type and addition of argon in the plasma gas. The influence of the deposition conditions on the carbon bonding and the hydrogen content of the films was then determined using Raman spectroscopy. Nanoindentation was used to determine the hardness of the samples, and a ball-on-disk test to investigate the friction coefficient. Results suggest that films with a lower sp2 content have both a higher hydrogen content and a higher hardness. This counterintuitive finding demonstrated that the carbon bonding is more important to hardness than the reported hydrogen concentration. The highest hardness obtained was 22.4 GPa. With the exception of a few films prepared using a pulsed voltage, all conditions gave DLC films having similarly low friction coefficients, down to 0.049.

Preparation of Aniline-Based Nitrogen-Containing Diamond-Like Carbon Films with Low Electrical Resistivity

The intrinsic high electrical resistivity of diamond-like carbon (DLC) films prevents their use in certain applications. The addition of metal or nitrogen during the preparation of the DLC films leads to a lower resistivity of the films, but it is usually accompanied by several disadvantages, such as a potential contamination risk for surfaces in contact with the film, a limited area that can be coated, deteriorated mechanical properties or low deposition rates of the films. To avoid these problems, DLC films have been prepared by plasma source ion implantation using aniline as a precursor gas, either in pure form or mixed with acetylene. The nitrogen from the precursor aniline is incorporated into the DLC films, leading to a reduced electrical resistivity. Film properties such as hardness, surface roughness and friction coefficient are nearly unchanged as compared to an additionally prepared reference sample, which was deposited using only pure acetylene as precursor gas.

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.

Generation and Applications of Plasma (An Academic Review)

Plasma being the fourth and most abundant form of matter extensively exists in the universe in the inter-galactic regions. It provides an electrically neutral medium of unbound negative and positive charged particles, which has been produced by subjecting air and various other gaseous mixtures to strengthen the electromagnetic field and by heating compressed air or inert gasses for creating negative and positive charged particles known as ions. Nowadays, many researchers are paying attention to the formation of artificial Plasma and its potential benefits for mankind. The literature is sparsely populated with the applications of Plasma. This paper presents specific methods of generation and applications of Plasma, which benefits humankind in various fields, such as in electrical, mechanical, chemical and medical fields. These applications include hydrogen production from alcohol, copper bonding, semiconductor processing, surface treatment, Plasma polymerization, coating, Plasma display panels, antenna beam forming, nanotechnology, Plasma Torch, Plasma pencils, low-current non-thermal Plasmatron, treatment of prostate cancer, Plasma source ion implantation, cutting by Plasma, Plasma etching, pollution control, neutralization of liquid radioactive waste, etc. Resultantly, worth of Plasma technology in the medical industry is increasing exponentially that is closing the gap between its benefits and cost of equipment used for generating and controlling it.

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.