The development of electrical plasma diagnostics for HiPIMS discharges

High power impulse magnetron sputtering (HiPIMS) is a plasma-based thin film deposition technique in which extremely high power pulses are applied to a conventional magnetron sputtering source. As a result, the plasma density in HiPIMS discharges is considerably increased up to 1E19 per cubic metre, about three orders of magnitude higher than that in conventional direct current magnetron sputtering (DCMS) discharges. Hence the vapour of the sputtered species becomes highly ionised, leading to remarkable improvement in the microstructure and the properties of depositing films. To better control the deposition process, it is important to gain insights into the properties and the dynamics of the HiPIMS plasmas. This thesis is associated with the investigations on HiPIMS plasmas using a number of electrical diagnostic tools including a Langmuir probe, a retarding field energy analyser and a gridded quartz crystal microbalance. It was shown, using a Langmuir probe analysis, that there are three distinct groups of electrons generated during first the 4 microseconds of the HiPIMS pulse. These electrons are super-thermal or beam-like electrons with effective temperatures of up to 100 eV, hot electrons with temperatures up to 7 eV and cold electrons with temperature

An Inverted Magnetron Operating in HiPIMS Mode

An ionized physical vapor deposition technique for thin ferromagnetic films is proposed. The technique is based on high power impulse magnetron sputtering (HiPIMS) with positive discharge polarity. A gapped-target was employed as the cathode of the magnetron. By applying positive HiPIMS pulses to the anode, sputtered particles inside the magnetron source were ionized and extracted through the gap. Using a discharge current with a peak of about 13 A, an ion flux in the order of 1021 m−2s−1 was obtained at a distance of 45 mm from the magnetron. In addition, deposition rates of up to 1.1 Å/s for nickel films were achieved using a 30 Hz repetition rate and 300 µs pulse width

Improvement of corrosion resistance and mechanical properties of chrome plating by diamond-like carbon coating with different silicon-based interlayers

In this study, the silicon-based interlayers for hydrogenated amorphous carbon (a-C:H) coating on a chromium-plated substrate are presented. The a-Si, a-Si:N, a-Si:H and a-Si _x C _y :H interlayers with a thickness of about 306 nm were deposited by direct current magnetron sputtering technique. The a-C:H films with a thickness of about 317 nm was prepared as a top layer by radio frequency-plasma chemical vapor deposition. The a-C:H films with silicon-based interlayers were characterized by x-ray photoelectron spectroscopy, Raman spectroscopy, field emission-secondary electron microscopy, nanoindentation, micro-scratching, and electrochemical corrosion measurements in terms of their structure, morphology, mechanical and adhesive properties, and corrosion resistance. The a-C:H films with an a-Si:H interlayer exhibit the lowest corrosion current density, which is about 36 times lower than that of the uncoated chromium-plated substrate. In addition, the hardness increases from 8.48 GPa for the uncoated substrate to 20.98 GPa for the a-C:H/a-Si:H sample. The mixing with hydrogen gas could reduce the residual oxygen during the deposition process, which could reduce the Si–O bonding and improve the adhesion strength between the a-C:H film and the a-Si:H interlayer and the a-Si:H interlayer and the substrate. Therefore, it can be concluded that the protective a-C:H coating with an a-Si:H interlayer has excellent potential to significantly improve the durability and extend the service life of materials used in abrasive and corrosive environments