N2 + O2 version on DN40CF flange; DN63CF flange size with ion sensor option
Typical operation power and frequency: 5 - 20 W / 2.5 GHz
Typical gas flow : 1 to 10 sccm
Suitable for different gas types ( for example N2, H2 or O2)
Additional equipment / options: all-metal valve, gas supply, RF generator, ion sensor, photo diode
The Free Microplasma Source FMP produces a pure localized plasma at the tip. This setup provides high purity plasma creation with effectively reduced wall interaction as well as a drastically reduced RF power consumption due to the small plasma size.
Main advantages of the FMP:
Free microplasma in front of injector, i.e.: reduced reactions with cavity materials
Cold plasma (low ion energy)
Multi-gas applications are possible
Wide gas flux range without reconfiguration: 1-10 sccm
Wide process chamber pressure range of 10-7 mbar to 10-2 mbar possible without reconfiguration (depending on pumping system)
No water cooling needed due to high efficiency plasma generation
Very low HF power needed due to microplasma
Simple and reliable operation
Compact setup on DN40CF (O.D. 2.75") mounting flange
The Free Microplasma Source FMP provides a pure localized plasma for substrate cleaning applications, surface preparation or layer growth within an UHV chamber or MBE system at low chamber pressure.
|The ion sensor of the FMP can also be used as a plasma probe (Langmuir probe). The measured currents and potentials in this system allow the determination of the physical properties of the plasma. The FMP creates a non-equilibrium and non-uniform plasma in front of the source. All plasma parameters which are determined from ion sensor measurements have to be interpreted carefully. However, the ion sensor measurements may be used as a process parameter forreliable and reproducible source operation.
Typical ion current characteristics of N2 and O2 plasma measured with the ion sensor Langmuir probe are shown below. The measured electron current (positive bias voltage) and ion saturation current (negative bias voltage) show a strong dependency on HF power and gas flow rate.
|The FMP comprises a viewport for optical access to the plasma. Using the viewport different measurements are possible, e.g. optical spectroscopy or operation and power control with a photo diode. Typical optical spectra from, N2, O2 and H2 are shown below.|
||DN40CF (O.D. 2.75”) /
DN63CF (O.D. 4.5”) with ion sensor option
|Thermocouple||NiCr/NiAl (type K)|
|Operating temperature||up to 300°C|
|In vaccum length L||287 mm (DN40CF O.D. 2.75'')
270 mm (DN63CF O.D. 4.5'') with ion sensor option
|In vacuum maximum total length TL||282 mm (DN63CF O.D. 4.5'') with ion sensor option|
|In vaccum outer diameter D||35 mm|
|Maximum airside length OL
|Maximum airside radius AR||196 mm|
||all-metal valve, gas supply, RF generator|
|Variants||-M (inert gas, e.g. N2, H2)
-T (reactive gas, e.g. O2)
|Options||ion sensor, photo diode|
|Schematic drawing of the Free Microplasma Source FMP
(drawing shows FMP 40
with optional ion sensor on DN63CF and gas supply)
For general information on CF mounting flanges see Flange and Gasket dimensions.
|[mm]||[mm] / [mm]||[W]||[A]||[V]|
|FMP-T||O2, N2||40-||L287 / D35||< 200||< 15||< 15|
||N2, H2||40-||L287 / D35||< 200||< 15||< 15|
|FMP-T||O2, N2||63-||L270 / D35||< 200||< 15||< 15|
||N2, H2||63-||L270 / D35||< 200||< 15||< 15|
|***||specify UHV length L with order|
e.g. FMP-T 40-L287D35
is a free microplasma source on DN40CF flange with UHV-length 287 mm and in-vacuum diameter 35 mm.