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