- N2+ O 2 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 Datasheet
Introduction
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
Application
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.
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.
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.
| 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 |
Dimensions
Specific data
For general information on CF mounting flanges see Flange and Gasketdimensions .
| Product | Gas type | CF flange | UHV dimensions*** [mm] | Power supply product code | Filament current | Filament voltage |
|---|---|---|---|---|---|---|
| [mm] | [mm] / [mm] | [W] | [A] | [V] | ||
| FMP-T | O2, N2 | 40- | L287 / D35 | < 200 | < 15 | < 15 |
| FMP-M | N2, H2 | 40- | L287 / D35 | < 200 | < 15 | < 15 |
| FMP-T | O2, N2 | 63- | L270 / D35 | < 200 | < 15 | < 15 |
| FMP-M | 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.
