Regulation Of The Metal Ionized Flux Fraction And Its Effect On The Properties Of Films Deposited By High Power Pulsed Magnetron Sputtering (HPPMS)

High power pulsed magnetron sputtering (HPPMS) is an newly developed physical vapor deposition (PVD) technology. It has high plasma densities up to 1018 m-3 and ionization fraction of the sputtered metal reaches 90%. However, due to the high target voltage and the confining magnetic field, most of metal ions can be trapped in front of the target and most of highly ionized sputtered atoms can not reach the substrate to contribute the film deposition, the ionization rate near the substrate is much lower than the ionization-fraction around the target. From the view of the industry application, the amount of ion in the vicinity of the substrate may be more important for the structure and mechanical properties of the deposited films. It is important to explore key factors effected the ion flux fraction and detect the ionization rate in front of the substrate for film deposition.Optical emission spectroscopy (OES) were applied to investigate composition of total ion fluxes and the flux fraction at different peak currents during titanium film deposition by HPPMS. Optical emission spectroscopy (OES) and a modified one-grid ion collector were used to study the composition of the plasma and the ionized metal flux fraction in front of the substrate at different peak current, respectively, and the relationship between the ionization fraction around the substrate and the film properties were study in detail. The results showed the ratio of the ionized metal species in the front of the substrate and the plasma density significantly increased with the peak target current increasing. While the deposition rate decreased drastically with the peak target current increasing. With the increase of the ionized metal species near the substrate, the residual stress of the film had changed from the tensile stress to compressive stress, and the film exhibited a smaller crystalline size and a flatter surface.To investigate effect of peak current on the microstructure and properties of TiN thin films deposited by high power pulsed magnetron sputtering (HPPMS), TiN films were fabricated on Si(100) and 316L stainless steel substrate. The result showed the deposition rate decreases as the peak current increasing at constant average power. At lower peak current, a (111) lattice planes are parallel to the substrate surface. At the higher peak current, the film exhibits a (111) preferential growth orientation due to intense ion bombardment. It is easier to generate a saturated TiN in higher peak current, and the film showed the strongest surface hardness and interfacial adhesion.