|frequently asked questions|
|what is plasma?
are there different kinds of plasmas?
what is the influence of the chamber wall on a plasma?
what are the differences between direct and remote plasma treatment?
what are the innovative features of CYRANNUS I plasma sources?
are these features not already known from other sources?
does it make sense to use microwave plasmas for industrial applications?
how much maintenance do CYRANNUS sources need?
are there restrictions for the application of CYRANNUS I plasma sources?
are microwave plasmas environmentally friendly?
what is the meaning of "CYRANNUS"?
|what is plasma?|
|Plasma is an energy containing gas. It is also called "the fourth state of matter": by increasing energy matter is transformed from solid to liquid state and from liquid to gaseous state. Even more energy input generates a plasma, consisting of ions, electrons and neutral particles.
Plasma is not a human invention: it is found in stars, in tails of comets or in flashes of lightning. Spectacular appearances of plasmas are the northern lights. The word "plasma" comes from the Greek and means "form" or "shape".
Yes, this is the case - common distinctions are:
CYRANNUS® technology generates a non-equilibrium and stationary kind of plasma.
Plasmas are usually contained in a chamber, e.g. a quartz tube. Concerning the interaction between the wall of that chamber and the plasma two cases are possible:
Plasma generated by a CYRANNUS® I source is dominated by gas phase processes.
The CYRANNUS® I plasma source can be configured for both, direct or remote applications.
It is true that some of the mentioned features are known from conventional plasma sources. However, until now there was no possibility to achieve the above mentioned properties simultaneously. E.g., plasmas at increased pressure were inhomogeneous or had only a small extension and operation time was short.
Up to now microwave plasmas were limited to a pressure range below 1 mbar as soon as spatial homogeneity was required. In consequence, the processing technology depended on a batch mode. CYRANNUS® I sources offer plasma generation up to atmospheric pressure as well as a symmetric configuration with two open flanges. These advantages allow a switch to an in-line production mode. The plasma sources are completely sealed. Customers are free to integrate the source into a given process. Connections are possible via standard flanges or with tailored adapters. These features come along with low maintenance requirements making CYRANNUS® technology attractive for industrial processes.
CYRANNUS® plasma sources are designed for long operating cycles without maintenance. Since the plasma process is excited via external coupling elements there is no direct contact between microwave coupling unit and plasma. A high reliability is given because continuous material attrition, e.g. on antennas or electrodes, does not exist. From time to time a cleaning of the plasma chamber may be appropriate. The sources´ design ensures an easy handling. The exchange of the quartz plasma chamber wall does not take more than 10 minutes.
Yes, there are some limitations for certain materials and set-ups. The energy coupling via microwaves may cause problems for the treatment of metallic materials. For such applications the electrical field distribution within the resonator has to be taken into consideration. Users should also think about remote plasma processes, were the plasma treatment occurs outside the resonator.
Plasma processes are environmentally friendly by nature, often they are working with pure air or oxygen. This is possible because the physical or chemical plasma reactions are based on the high particle energy and not on electrochemical potentials (like e.g. in wet chemical processes). This avoids recycling or disposal of chemical waste.
The name CYRANNUS® is an acronym of CYlindrical Resonator with ANNUlar Slots which is the main item of the CYRANNUS® I plasma source.