Characterization of transport of neutral and ionized species in reactive HiPIMS process
The aim of this study is to control the deposition in real time of thin films produced by plasma processes. In our case, the thin films are obtained by the HiPIMS (high power impulse magnetron sputtering ) plasma regime since it is one of the only physical processes currently able to ensure optimal compliance of the coatings on complex 3D substrates. Thenceforth and in order to control this process, the effects of the experimental parameters of the discharge should be correlated with the properties of the deposits, including thickness and crystallinity. Two time resolved plasma diagnostics were investigated: optical emission spectroscopy and mass spectrometry.
Measurements of optical emission spectroscopy (OES) have been carried out to obtain the composition of the plasma. The influence of multiple parameters on coatings and on the plasma as the pressure, the distance from the target, the surface power density, the discharge duration and gas mixture is studied. Correlations between thickness and OES measurements on the neutral Ti were found. The first one allows to link the tD discharge time, the thickness of the deposit (determined by profilometry and scanning electron microscope SEM) and the intensity of the emission line of the neutral titanium Ti at 365 nm. The second correlation highlights a proportional variation between the percentage of O2 in the Ar/O2 gas mixture, the thickness and the intensity of the Ti-neutral emission line at 365 nm.
The influence of the substrate temperature range between 0 and 500 °C on the crystallinity of TiO2-type deposits in DC (direct current)  and HiPIMS processes  was also studied. Our results lead that the use of the ions generated in HiPIMS mode should provide good crystallinity at lower temperatures than in DC mode.
 A. Anders, Tutorial : Reactive high power impulse magnetron sputtering (r-hipims), Applied Physics Review 121 (2017).
 Wei Zhou et al : Low temperature deposition of nanocrystalline TiO2 films: enhancement of nanocrystal formation by energetic particle bombardment J. Phys. D: Appl. Phys. 40 219 (2007)
 S.Konstantinidis et.al, Titanium oxide thins films deposited by high-power impulse magnetron sputtering, Thin Solid Films 515 (2006).