ometry are deposited on substrates that are fixed on holders undergoing
planetary motion。 The arrangement also allows one a simple deposition of multi- and nano-layers with sharp interfaces。 It was successfully operating in the production with a relatively low emission of droplets。
The recently developed more advanced system(13) is shown in Fig。 2。
It consists of two (or more) independent cylindrical, rotating cathodes with a very strong magnetic field。 The latter is induced by a combination
Fig。 1。 Schematics of the central cathode with two separate and independently operated vacuum arcs。
of linear array of strong permanent magnets and magnetic coil that in combination produce a strong magnetic field perpendicular to the axis of the cathode and concentrated into a narrow region where the arc is fast moving up and down (see Fig。 3, Ref。 13)。 This enables us to achieve a high plasma density at the substrates (coated tools) and also a very uni- form erosion of the cathodes。 Because of the uniformity of the erosion, the cylindrical cathodes reach significantly longer life-time than the planar ones of a similar total area。
The new LARC® technology combines the advantages of the rotat- ing cathodes and their positioning on the side of the chamber (Fig。 3)。(14) The asymmetric position of the cathodes in the door for loading and
unloading of the tools results automatically in a deposition of nano-lay- ered nanocomposite coatings。 Another advantage is the possibility of the pre-cleaning of the cathodes by means of a Virtual Shutter®(13) when the evaporated material is directed away from the substrates prior to the depo- sition of the coating (see Fig。 3)。 The advanced design and high magnetic field enables one to reliably operate and evaporate from a pure aluminum cathode。
Fig。 2。 Coating unit “MARWIN” with two rotating central cathodes C and the tool holders H。
3。PROPERTIES OF THE COATINGS
3。1。The Binding State of Silicon
The important difference between the coatings consisting of the metastable (Al, Ti, Si)N solution that are deposited by the conven- tional vaccum arc technology under negative bias (“ion plating”)(11) and the present superhard nc-(Al1−x Tix )N/a-Si3N4 nanocomposites is the chemical binding nature of silicon。 By analogy with the earlier studied
(9, 10, 15, 16)
nc-(Al1−x Tix )N/a-Si3N4 and other
superhard nanocomposites we
had to verify if the silicon is in its “metallic state” dissolved in the (Al,
Ti, Si)N metastable solution or if it is bonded as in the non-metallic Si3N4。 X-ray photoelectron spectroscopy, XPS, enabled us to distinguish these different binding states because of the clear differences in the bind- ing energy of the Si 2p electrons as seen in Table I。
Although the AlKα radiation provides a good signal-to-noise ratio, the Si 2p region, which is of the fundamental interest here, is interfered by
Fig。 3。 The new coating unit π 80 that was developed jointly by PLATIT AG and SHM Ltd。(14)
the A1 KLL Auger signal and by a weaker Kα5,6 satellite of the Al 2s line, whose position overlaps with the Si 2p signal from TiSi2 and elemental Si。 When using the MgKα radiation, the Al KLL Auger signal is shifted away of the Si 2p region but a new problem arises: Because the Mg anode has to be operated at a much smaller power, a significantly longer time for the measurement is necessary in order to obtain a sufficient signal-to- noise ratio that is needed in order to distinguish between the weak second satellite MgKα5,6 of the Al 2s XPS signal and the Si 2p signal from TiSi2 and elemental silicon。 Moreover, this spectral region is also interfered by 新型超硬纳米复合材料英文文献和中文翻译(3):http://www.youerw.com/fanyi/lunwen_92149.html