The interaction between plasma and injected micro-disperse powder particles might be used as a tool for the study of plasma wall processes in technological applications of low pressure plasmas. Powder particles have been used, for instance, as micro-probes for the determination of the electric field in front of electrodes and substrates as well as for the observation of the energy fluxes between plasma and surfaces.

If dust particles are injected into a plasma, they are negatively charged and confined in the discharge. The trapping is due to the balance of the forces acting on the particles. By observing the position and movement of the particle in dependence on the discharge parameter one can obtain information on the electric field in front of surfaces where other plasma diagnostic methods fail.

In addition, the particles have also been used as microscopic thermal probes. The equilibrium temperature of the particles, which is a result of the several energy fluxes from the plasma, has been determined by temperature-dependent fluorescence of laser dye mixed with the micro-particles. By considering the involved energy gain and loss mechanisms, respectively, the thermal balance of the particles has been estimated and the resulting equilibrium temperature has been compared with the particle temperature measurements. In case of an argon plasma the heating of the particles by charge carrier recombination could be identified as dominant energetic contribution, while the losses are due to radiation and conduction.

The growth process of some metallic films ( of 0.4 nm to 150 nm nominal thickness) by sputtering method was investigated through the characterization of electrical properties, microstructure and crystallite size of the films. To make clear the influence of sputtering conditions on the process, the conditions were varied as follows: target - substrate distance (40 mm or 55 mm), substrate temperature (room temperature, 100°C, 400°C), gas pressure (8 - 20 mTorr) and rf power (25 - 40 W). It is generally known that the electrical resistivity increases with reducing thickness, and an abrupt increse occurs due to the change in films state from continuous to discontinuous.

In the case of Pt film deposition, there was negligiable difference on films among various sputtering conditions. And they were continuous state at about 1 nm. This is closely related to the nature of Pt film, which easily grows in 2-dimensional mode. And influence of sputtering conditions is less. However, in the case of Al, thickness where the abrupt increase on the resistivity occurs, very much depended on the sputtering conditions and was from 1 nm to 10 nm. From the results of AFM observation, film deposited under better condition has larger grain size and lower RMS and Ra value. Film deposited on the heated substrate consists of much larger grains, it became continuous state at higher thickness because of the agglomeration. Consequently, influence of the deposition condition on the film growth by sputtering is very much related to the nature of the films.

Conventional reactive sputtering process with oxygen or nitrogen exhibits nonlinear effects such as hysteresis loops of deposition parameters like the target potential or the reactive gas partial pressure. Such instabilities are usually prevented by implementing particular devices or feedback control systems.

In the present paper, we consider an original way to avoid target poisoning by using a well controlled pulsed flow of the reactive gas ^{1, 2}. This reactive gas pulsing technique is used to deposit titanium oxide thin films. Real time electrical characterization of the Ti target and in situ analyses of the reactive atmosphere are currently performed so as to understand and follow kinetics of poisoning and cleaning of the target surface. The effects of the oxygen flow modulation pattern on the deposition rate, structural and morphological properties as well as optical and electrical characteristics of the films are investigated. The pulsing method leads to an increase of the deposition rate (up to 70 % of the pure metal rate) and allows to prepare conductive (σ = 11 S.m^-1 at room temperature) and transparent coatings. Relationships between process parameters like oxygen partial pressure or target poisoning and physical behaviors of the deposited material are discussed.

Furthermore, our results suggest that the reactive gas pulsing technique tested with TiO₂ to improve the deposition rate and some properties is also suitable to nitride compounds. ¹ A.J. Aronson, D. Chen and W.H. Class, Thin Solid Films, 72 (1980) 535 ² R.P. Howson, N. Danson and I. Safi, Thin Solid Films, 351 (1999)32.

9,10-anthraquinone; 1,4-dihydroxy-9,10-anthraquinone and 1,8-dihydroxy-9,10-anthraquinone films have been grown by thermal evaporation technique onto the glass substrate kept at different temperatures in a vacuum of 10^-5 torr. The experimental conditions are optimised to obtain better crystallinity of the films. The films so prepared have been studied for their electrical conductivity, carrier concentration, drift mobility, optical properties and electron microscopy.

Observations reveal that the electrical conductivity of dihydroxy-9,10-anthraquinone films is more as compared to 9,10-anthraquinone films. The conduction in these films is found to be ohmic in nature. The electrical conductivity and carrier concentration of films increases with the increase in temperature(300-413K), while the drift mobility decreases. The films deposited at higher substrate temperature appear to be more ordered . Results on optical absorption studies indicate the band gap energies in the range of 2.0-3.5 eV. The frequencies of the IR absorption bands for the films are in good agreement with the powder samples taken as reference.