P. Ksirova

Angular dependence of plasma parameters and film properties during high power impulse magnetron sputtering for deposition of Ti and TiO2 layers

Angular distribution measurements have been carried out during High Power Impulse Magnetron Sputtering (HiPIMS) of a titanium target and deposition of titanium and titanium oxide films. The HiPIMS system was operated at a repetition frequency f = 100 Hz with a duty cycle of 1%. Langmuir probe diagnostics has been carried out at a distance of 7.5 cm from the target at four different angles with respect to the surface normal of the target. Film properties were investigated by means of SEM, XR, and GIXD, and a dependence of film thickness and crystalline structure on the deposition angle is observed.

Enhanced oxidation of TiO2 films prepared by high power impulse magnetron sputtering running in metallic mode

A method is introduced that allows suppressing unwanted effects of target poisoning during reactive high-power impulse magnetron sputtering (R-HiPIMS) employed for deposition of oxide films. The method, based on higher reactivity of excited/activated oxygen species, is studied and demonstrated on TiO2 films deposited in R-HiPIMS discharge running very close to the metallic mode with a high deposition rate. An external source of energetic plasma that activates oxygen gas, delivered to the vicinity of the substrate, is combined with conventional R-HiPIMS of the Ti target. The activated oxygen species enable reducing the total flow rate, which simultaneously results in suppression of the target poisoning effect. On the other hand, sufficient oxidation and growth of transparent crystalline TiO2 films were observed.A method is introduced that allows suppressing unwanted effects of target poisoning during reactive high-power impulse magnetron sputtering (R-HiPIMS) employed for deposition of oxide films. The method, based on higher reactivity of excited/activated oxygen species, is studied and demonstrated on TiO2 films deposited in R-HiPIMS discharge running very close to the metallic mode with a high deposition rate. An external source of energetic plasma that activates oxygen gas, delivered to the vicinity of the substrate, is combined with conventional R-HiPIMS of the Ti target. The activated oxygen species enable reducing the total flow rate, which simultaneously results in suppression of the target poisoning effect. On the other hand, sufficient oxidation and growth of transparent crystalline TiO2 films were observed.

Optical emission spectroscopy of High Power Impulse Magnetron Sputtering (HiPIMS) of CIGS thin films

CuIn1-xGaxSe2 (CIGS) thin films with x = 0, 0.28 and 1 were prepared by the sputtering of Cu, In and Ga in HiPIMS (High Power Impulse Magnetron Sputtering) or DC magnetron and subsequently selenized in an Ar+Se atmosphere. Optical emission spectroscopy (OES) was used to monitor differences in HiPIMS and DC plasma during sputtering of metallic precursors. Thin film characteristics were measured using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDX) and other techniques.

Preparation of CIGS thin films by HiPIMS or DC sputtering and various selenization processes

Abstract CuIn1-xGaxSe2 (CIGS) thin films were prepared by the sputtering of metallic precursors Cu, In, Ga in HiPIMS (High Power Impulse Magnetron Sputtering) or DC magnetron and subsequently selenized in an atmosphere of pure Se or Ar+Se. The average absorbed power and discharge current were the same in the HiPIMS and DC plasma. The basic aim of this work was to compare the structural properties of the CIGS films as a function of magnetron excitation mode and selenization thermal treatment conditions. Film characteristics were measured using X-ray diffraction, scanning electron microscopy, Raman spectroscopy, energy-dispersive X-ray spectroscopy and other techniques. All the CIGS films revealed the chalcopyrite crystal structure with a preferential (112) orientation. Only a very small influence of magnetron excitation mode on thin film properties was observed. On the other hand, selenization in Ar+Se atmosphere led to bigger grain size, better crystallinity and a significantly higher level of Ga substitution.