Abstract
In earlier work, we have shown that in filament-enhanced plasma assisted CVD, increasing the degree of ionisation, reducing the voltage applied to the cathode and reducing the C/H ratio in the plasma produces improved DLC films giving a higher optical band gap and a lower hydrogen content. In that work the possibility of increasing the level of ionization was limited. We describe here an improved discharge layout which can provide specimen (cathode) current densities several orders of magnitude higher, across a wider pressure range. This produces films with a hardness of over 8000 HK (200 g) at a deposition rate of2-3μm/h on stainless steel and mild steel, in a methane/hydrogen plasma containing 0.5-1.0% methane. The morphology of the film surface is faceted, smoother than as-deposited films reported elsewhere, but reminiscent of those smoothed by post-deposition argon bombardment.
Original language | English |
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Pages (from-to) | 1305-1309 |
Number of pages | 5 |
Journal | Vacuum |
Volume | 46 |
Issue number | 11 |
DOIs | |
Publication status | Published - 1995 |
Keywords
- Carbon
- Carbon steel
- Composition effects
- Current density
- Electric discharges
- energy gap
- Film growth
- Ionization of solids
- Morphology
- Plasma applications
- Stainless steel
- Surfaces