High-power pulsed magnetron discharges have drawn an increasing interest as an approach to produce highly ionized metallic vapor. In this paper we propose to study how the plasma composition and the deposition rate are influenced by the pulse duration. The plasma is studied by time-resolved optical emission and absorption spectroscopies and the deposition rate is controlled thanks to a quartz microbalance. The pulse length is varied between 2.5 and 20 s at 2 and 10 mTorr in pure argon. The sputtered material is titanium. For a constant discharge power, the deposition rate increases as the pulse length decreases. With 5 s pulse, for an average power of 300 W, the deposition rate is ϳ70% of the deposition rate obtained in direct current magnetron sputtering at the same power. The increase of deposition rate can be related to the sputtering regime. For long pulses, self-sputtering seems to occur as demonstrated by time-resolved optical emission diagnostic of the discharge. In contrary, the metallic vapor ionization rate, as determined by absorption measurements, diminishes as the pulses are shortened. Nevertheless, the ionization rate is in the range of 50% for 5 s pulses while it lies below 10% in the case of a classical continuous magnetron discharge.

A flowing afterglow of very pure molecular nitrogen at atmospheric pressure with admixture of controlled amounts (from some tens to some thousands ppm) of molecular oxygen is studied. For flows of 40 slm, spectroscopic measurements down the discharge allow us to estimate concentrations in atomic nitrogen and in singlet-S metastable oxygen atoms. With UV emission due to nitrogen oxide, all three reactive agents exhibit sporicidal effects, and their relative role is estimated.

A nitrogen afterglow at atmospheric pressure has recently been described as able to transport active species over long distances in small diameter tubes, with a biocidal effect. For a discharge gas composed of nitrogen, either of high purity or with some controlled ppm of oxygen, survival curves are presented. The afterglow, flowing at 40 slm in a cylindrical quartz tube with 8 mm internal diameter is studied using emission spectroscopy. Fundamental or excited states of atomic or molecular species of parent gases are detected and evaluated. Their absolute concentration is measured along the tube axis. Correlated to transport equations, results give information on the creation and destruction reactions of these species, especially of the O(1S) metastable state of O, the species that has been shown to boost the biocidal effect.

Transporting metallic ions from the magnetron cathode to the substrate is essential for an efficient thin-film deposition process. This letter examines how inductively coupled plasma superimposed onto a high-power pulsed magnetron discharge can influence the mobility of titanium ions. To this effect, time-resolved optical emission and absorption spectrometry are conducted and the current at the substrate is measured. With this new hybrid technique, ions are found to reach the substrate in two successive waves. Metal ions, only present in the second wave, are found to accelerate proportionally to the power supplied to the inductively coupled plasma. All the measurements in this study are made at 10 and 30mTorr, with 10μs long pulses at the magnetron cathode.

Absorption spectroscopy measurements of argon metastable and resonant atom density in atmospheric pressure Ar-He surface-wave plasmas using a low pressure lamp

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Modern medicine is still struggling to find new and more effective methods for fighting off viruses, bacteria and fungi. Among the most dangerous and at times life-threatening fungi is Candida albicans. Our work is focused on surface and structural characterization of hydroxyapatite, silver doped hydroxyapatite and zinc doped hydroxyapatite deposited on a titanium substrate previously coated with polydimethylsiloxane (HAp-PDMS, Ag:HAp-PDMS, Zn:HAp-PDMS) by different techniques: Scanning Electron Microscopy (SEM), Glow Discharge Optical Emission Spectroscopy (GDOES) and Fourier Transform Infrared Spectroscopy (FTIR). The morphological studies revealed that the use of the PDMS polymer as an interlayer improves the quality of the coatings. The structural characterizations of the thin films revealed the basic constituents of both apatitic and PDMS structure. In addition, the GD depth profiles indicated the formation of a composite material as well as the successful embedding of the HAp, Zn:HAp and Ag:HAp into the polymer. On the other hand, in vitro evaluation of the antifungal properties of Ag:HAp-PDMS and Zn:HAp-PDMS demonstrated the fungicidal effects of Ag:HAp-PDMS and the potential antifungal effect of Zn:HAp-PDMS composite layers against C. albicans biofilm. The results acquired in this research complete previous research on the potential use of new complex materials produced by nanotechnology in biomedicine.

This paper deals with the diagnostics of a high power pulsed magnetron sputtering device (HPPMS). The HPPMS plasma was spatially and temporally characterized in the post-discharge using optical absorption spectroscopy and Langmuir probe time resolved measurements. A circular titanium target was used, the buffer gas was argon and the pressure was fixed at 4 Pa. The titanium densities (neutrals and ions) were measured by a pulsed resonant absorption spectroscopy technique. We found an ionization degree higher than 0.5. Comparison beetween the experimental results and a simple one-dimensional model of diffusion shows that in these conditions, the transport of neutral and ionized sputtered atoms is mainly controlled by diffusion (ambipolar diffusion for ions).