Ladislav Bardos

Radio frequency plasma jet applied to coating of internal walls of narrow tubes

A novel method for deposition of thin films onto internal walls of narrow tubes is described. The method is based on sputtering and/or evaporation of the end of a nozzle in a radio frequency plasma jet system (RPJ). A Ti nozzle of 5 mm outer and 2 mm inner diameter, respectively, was used for TiNx film deposition onto Si substrate inserts fixed on the internal wall of a steel tube of 8 mm bore. The axial distribution of the film thickness along 20–50 mm of deposited area was measured. An effect of separation of macroparticles was found in the RPJ. This enabled the growth of high quality films on the tube walls at rf power levels exceeding 100 W.

Linear arc discharge source for large area plasma processing

A linearly scalable plasma source based on the radio frequency generated hot hollow cathode discharge between two parallel plates with a magnetic field perpendicular to the plates near the outlet of the cathode is introduced. The magnetic field facilitates and confines the hollow cathode discharge which leads to a high power density and a high cathode wall temperature. The geometry and location of hot zones is directly controlled by magnetic field. The linear arc discharge (LAD) source exhibits similar features as the cylindrical radio frequency hollow cathode plasma jet. Experiments indicate a metastable assisted growth of TiN films. LAD source extends abilities of the radio frequency hollow cathode plasma jet to the large area processing.

Metastable assisted deposition of TiN films

An excess heat from an exothermic reaction of metastable Ar (43P0) and Ar (43P2) atoms with N2 molecules at low contents of N2 in Ar was found to be responsible for an enhanced thermionic emission, an enhanced production of Ti target vapor, an increased ionization, and consequently for an enhanced deposition rate of TiN films in the radio frequency hollow cathode plasma jet (RHCPJ). This finding emphasizes favorable geometry of hollow cathodes, as well as an important role of metastables in plasma‐assisted processes.

Deposition of Carbonaceous Films onto Internal Walls of Tubes

Deposition of carbonaceous films onto inner walls of small diameter tubes was been studied. A small size radio frequency plasma jet system with nozzles made from tungsten or graphite has been installed coaxially inside the tube. Changes in H 2 +CH 4 (+O 2 ) gas compositions affected strongly the coating conditions on inner walls of the tube. The growth rate distributions of the microcrystalline primarily sp 3 bonded film along the substrate area indicate an important role of the afterglow and peripheral regions of the plasma jet. Films were deposited onto Si, Mo, W, Cu, and Fe surfaces. At particular conditions incorporation of the substrate material into the growing films was observed

Patterning of silicon wafers using the plasma jet dry etching technique

Abstract A very high rate dry etching system based on the plasma jet principle has recently been presented. With this device it is possible to create high concentrations of reactive species. This is done by passing the active gases through a hollow cathode discharge inside a nozzle. A jet stream of radicals will be formed. Silicon substrates can be etched by placing them in the jet stream. With this new technique it is possible to obtain etch rates in silicon which are two orders of magnitude larger than obtained by standard dry etching techniques. Aluminum and SiO 2 have been investigated as mask materials in order to study the possibility of using the plasma jet for micro-patterning. The influence of different processing parameters on the etched structures has been studied.