Understanding of hybrid PVD–PECVD process with the aim of growing hard nc-TiC/a-C:H coatings using industrial devices with a rotating cylindrical magnetron

Principles and practice of an automatic process control for the deposition of hard nc-TiC/a-C:H coatings by hybrid PVD-PECVD under industrial conditions

“…The changes of the plasma parameters were related to changes of the target surface state. A similar, yet more pronounced, behavior of the deposition parameters was reported in our previous work where an industrial-scale sputtering device with a central rotating cylindrical titanium cathode was used to deposit titanium-carbon coatings [26].…”

“…Thus, two sudden changes of the conditions in the deposition chamber were observed. For an acetylene supply of 60 sccm, the target suddenly changed its state from being titanium rich to being covered by a TiC compound, as was discussed in our previous paper [26]. For an acetylene supply of 144 sccm, the target suddenly changed its state from being covered by the TiC compound to being covered by a carbon-rich layer.…”

“…The highest hardness of the coatings was always achieved for the acetylene supply corresponding to the conditions of the voltage drop independently of the thickness of the target [26]. However, although this process did not suffer from hysteresis, the nominal supply of acetylene needed for the voltage drop-thus, for the conditions to grow the coating of maximal hardness-still varied with the target thickness [26].…”

“…Both the cathode voltage and the total pressure were nearly constant for even higher acetylene flows. The relationship among the process parameters, the deposition plasma properties and the coating properties for the conditions corresponding to the voltage drop were studied in our previous paper [26]. The voltage drop was explained by the phase transition of the target surface from Ti/TiC to TiC, which caused a change in the target's secondary electron emission coefficient.…”

“…However, although this process did not suffer from hysteresis, the nominal supply of acetylene needed for the voltage drop-thus, for the conditions to grow the coating of maximal hardness-still varied with the target thickness [26]. Therefore, an optimal acetylene flow to deposit the hard coating cannot be determined in advance as it depends on the target erosion.…”