Plasma sources

 

 

 

 

 

 

 

 

 

  

HCD-L 300

13,56 MHz hollow cathode plasma source

 

Features:

  • operation over an extended power and pressure range
  • no mode jumps
  • high plasma and radical species densities with excellent axial homgeneity
  • compatible with chemical reactive and non-reactive gases
  • cw and pulsed power operation
  • low contamination
  • scaleable

Applications:

  • plasma-enhanced chemical vapor deposition (PE-CVD)
  • plasma polymerisation
  • surface modification
  • plasma cleaning
  • plasma etching
  • reactive and non-reactive ion etching
  • basic reasearch in the material sciences

Hollow cathode discharges represent a relatively simple means for the efficient production of high density, low temperature plasmas.
The plasma source HCD L-300 employs the hollow cathode effect. In principle, the HCD L-300 consists of two cylindrical tubes aligned coaxially. The innner tube enclosing the plasma is rf powered; the outer tube is electrically grounded. Along the cylindrical axis multiple holes are drilled into the inner and outer cylinder allowing plasma jets to be extracted after the primary plasma has been excited in the hollow cathode. A proprietary internal cathode structure guaranties a homogeneous plasma jet formation over extended source lenghts.
The HCD L-300 extends over a length of 300 mm. By stacking together two or three HCD L-300 total source lenghts are 600 (HCD L-600) and 900 mm (HCD L-900), respectively.

Performance
There are two major parameters controlling the performance and technical applicability of hollow cathode plasma sources such as the HCD L-300. These are the working pressure range of the hollow cathode (primary) discharge and the rf power required for plasma breakdown, i.e. ignition. Once the plasma is excited the rf power can be varied over an extended power and pressure range without affecting the stability of the discharge and overall plasma jet formation. When further reducing the rf power, there is a minimum where the plasma no longer is stable.


Lifetime


The HCD L-300 is manufactured using exclusively aluminum and ceramic parts for electrical insulation. No quartz windows etc. are necessary. Since all ceramic parts are shielded from direct plasma interaction and sputtering the source is extemly robust and offers extended lifetimes often superior to those of inductively and microwave excited plasmas.

 

Technical data

Rf power (max):  300 W (air cooled)

                           1000 W (water cooled)

Frequency          13.56 MHz

pressure range:   5...1000 Pa

Gas flow rate:      5...300 sccm

 

Application note: