MBE Components, Free Microplasma Source FMP


Free Microplasma Source


FMP 40
FMP 40 Free Microplasma Source with optional gas supply on DN40CF (O.D. 2.75") flange
  • 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

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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.

O2 plasma in front of FMP

Plasma probe measurement with ion sensor

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.
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Spectroscopy measurements with viewport

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.
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Technical data

Mounting flange
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
Bakeout temperature 250°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
517 mm
Maximum airside radius AR 196 mm
Additional equipment
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 FMP Schematic drawing of the Free Microplasma Source FMP

(drawing shows FMP 40
with optional ion sensor on DN63CF and gas supply)


Specific data

For general information on CF mounting flanges see Flange and Gasket dimensions.

images/header_filament_current.gif images/header_filament_voltage.gif
[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


Product code:

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.


Related products

The following list provides suggestions for related products. For additional product suggestions or more detailed information, please contact us.


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